About
PrimeGrid's primary goal is to advance mathematics by enabling everyday computer users to contribute their system's processing power towards prime finding. By simply
downloading and installing BOINC and attaching to the PrimeGrid project,
participants can choose from a variety of prime forms to search. With a little patience, you may find a large or even record
breaking prime and enter into Chris Caldwell's The Largest Known Primes Database with a multi-million digit prime!
PrimeGrid's secondary goal is to provide relevant educational materials about primes. Additionally, we wish to contribute to the
field of mathematics.
Lastly, primes play a central role in the cryptographic systems which are used for computer security. Through the study of prime
numbers it can be shown how much processing is required to crack an encryption code and thus to determine whether current
security schemes are sufficiently secure. PrimeGrid is currently running several sub-projects:
- 321 Prime Search: searching for
mega primes of the form 3·2n±1.
- Cullen-Woodall Search: searching for
mega primes of forms n·2n+1 and
n·2n−1.
- Generalized Cullen-Woodall Search: searching for mega primes of forms n·bn+1 and
n·bn−1 where n + 2 > b.
- Extended Sierpinski Problem: helping solve the Extended Sierpinski Problem.
- Generalized Fermat Prime Search: searching for
megaprimes of the form b2n+1.
- Prime Sierpinski Project: helping the Prime Sierpinski Project solve the Prime Sierpinski Problem.
- Proth Prime Search: searching for primes of the form k·2n+1.
- Seventeen or Bust: helping to solve the Sierpinski Problem.
- Sierpinski/Riesel Base 5: helping to solve the Sierpinski/Riesel Base 5 Problem.
- The Riesel problem: helping to solve the Riesel Problem.
- AP27 Search: searching for record length arithmetic progressions of primes.
Recent Significant Primes
On 22 June 2024, 23:51:45 UTC, PrimeGrid's Generalized Fermat Prime Search found the Mega Prime
9332124524288+1
The prime is 3,654,278 digits long and will enter The Largest Known Primes Database ranked 12th for Generalized Fermat primes and 85th overall.
The discovery was made by Detlef Lexut ( [SG]KidDoesCrunch) of Germany using an NVIDIA GeForce RTX 3090 in an Intel(R) Core(TM) i9-10940X CPU @ 3.30GHz with 64GB RAM, running Microsoft Windows 11 Professional x64 Edition. This computer took about 27 minutes to complete the probable prime (PRP) test using Genefer22. Detlef Lexut is a member of the SETI.Germany team.
The PRP was confirmed prime on 23 June 2024 by an AMD Ryzen 9 5950X @ 3.4GHz with 128GB RAM, running Linux Mint 20.3. This computer took about 15 hours, 43 minutes to complete the primality test using LLR.
For more information, please see the Official Announcement.
On 19 June 2024, 5:29:47 UTC, PrimeGrid's Generalized Fermat Prime Search found the Mega Prime
10913140524288+1
The prime is 3,689,913 digits long and will enter The Largest Known Primes Database ranked 11th for Generalized Fermat primes and 81st overall.
The discovery was made by Heinrich Podsada ( PoHeDa) of Germany using an NVIDIA GeForce RTX 3070 in an AMD Ryzen 9 5950X 16-Core Processor @ 3.40GHz with 64GB RAM, running Microsoft Windows 11 Professional x64 Edition. This computer took about 50 minutes to complete the probable prime (PRP) test using Genefer22. Heinrich Podsada is a member of the SETI.Germany team.
The PRP was confirmed prime on 20 June 2024 by an AMD Ryzen 9 5950X @ 3.4GHz with 128GB RAM, running Linux Mint 20.3. This computer took about 15 hours, 56 minutes to complete the primality test using LLR.
For more information, please see the Official Announcement.
On 13 April 2024, 3:42:53 UTC, PrimeGrid's Generalized Fermat Prime Search found the Mega Prime
8630170524288+1
The prime is 3,636,472 digits long and will enter The Largest Known Primes Database ranked 11th for Generalized Fermat primes and 83th overall.
The discovery was made by Antonio Lucendo ( Trotador) of Spain using a dual CPU AMD EPYC 7B13 64-Core Processor @ 2.20GHz with 173GB RAM, running Ubuntu 22.04.3 LTS. This computer took about 4 hours, 45 minutes to complete the probable prime (PRP) test using Genefer22. Antonio Lucendo is a member of the XtremeSystems team.
The PRP was confirmed prime on 14 April 2024 by an AMD Ryzen 9 7950X3D @ 4.2GHz, running Debian 12.5. This computer took about 26 hours, 11 minutes to complete the primality test using LLR.
For more information, please see the Official Announcement.
Other significant primes
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News 
A Call to Arms! We Need Your Help!
A message from Stream regarding the Primorial project and the upcoming challenge:
Attention! More primorial sieving is required on GFN Server!
Considering insane computing power added during challenges, it may happen that we'll reach 10M during primorial challenge. Next range (10M-25M) was added to the sieve file later and currently is not sieved completely. There is a gap in sieving between 15T-40T, i.e. inside relatively low range where lot of factors will be found. I planned to sieve it myself, eventually (80 days for a single 4070) but we're already progressing very fast and challenge will push leading edge even further.
To make challenge most efficient and avoid testing of useless candidates which can be removed by sieving, please return back for few days to the primorial sieve on GFN Server. Current sieving leading edge is 1067T. At 1070T server will automatically jump back to 15T and return to old position after 40T. I hope that such a small range (25T) will take only few days with combined effort and complete sieve file will be ready before challenge.
2 Aug 2024 | 19:00:04 UTC
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International Cat Day Challenge on new Primorial Search BOINC project
From August 8th 08:08:00 UTC to August 13th 08:08:00 PrimeGrid will be running a 5 day challenge on the newly migrated Primorial Search (PRS) project. Note the unusual start and end times!
For more information, please see this forum thread.
1 Aug 2024 | 11:21:24 UTC
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Another GFN 19 Found!
On 22 June 2024, 23:51:45 UTC, PrimeGrid's Generalized Fermat Prime Search found the Mega Prime:
9332124^524288+1
The prime is 3,654,278 digits long and will enter “The Largest Known Primes Database” ranked 12th for Generalized Fermat primes and 85th overall.
The discovery was made by Detlef Lexut ([SG]KidDoesCrunch) of Germany using an NVIDIA GeForce RTX 3090 in an Intel(R) Core(TM) i9-10940X CPU @ 3.30GHz with 64GB RAM, running Microsoft Windows 11 Professional x64 Edition. This computer took about 27 minutes to complete the probable prime (PRP) test using Genefer23. Detlef Lexut is a member of the SETI.Germany team.
The PRP was confirmed prime on 23 June 2024 by an AMD Ryzen 9 5950X @ 3.4GHz with 128GB RAM, running Linux Mint 20.3. This computer took about 15 hours, 43 minutes to complete the primality test using LLR.
For more details, please see the official announcement.
15 Jul 2024 | 22:36:13 UTC
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GFN 19 Found!
On 19 June 2024, 05:29:47 UTC, PrimeGrid's Generalized Fermat Prime Search found the Mega Prime:
10913140^524288+1
The prime is 3,689,913 digits long and will enter “The Largest Known Primes Database” ranked 11th for Generalized Fermat primes and 81st overall.
The discovery was made by Heinrich Podsada (PoHeDa) of Germany using an NVIDIA GeForce RTX 3070 in an AMD Ryzen 9 5950X 16-Core Processor @ 3.40GHz with 64GB RAM, running Microsoft Windows 11 Professional x64 Edition. This computer took about 50 minutes to complete the probable prime (PRP) test using Genefer23. Heinrich Podsada is a member of the SETI.Germany team.
The PRP was confirmed prime on 20 June 2024 by an AMD Ryzen 9 5950X @ 3.4GHz with 128GB RAM, running Linux Mint 20.3. This computer took about 15 hours, 56 minutes to complete the primality test using LLR.
For more details, please see the official announcement.
15 Jul 2024 | 22:27:37 UTC
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Project finances
Please visit the forums to find an update on the project finances.
Any donations for the project are greatly appreciated. Please visit the donations page if you want to support the project financially. Thank you!
18 Jun 2024 | 10:56:33 UTC
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... more
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Newly reported primes(Mega-primes are in bold.)
238193230^131072+1 (Scott Brown); 2403*2^1985052+1 (Randall J. Scalise); 238168282^131072+1 (Scott Brown); 405044660^65536+1 (AlHo); 40460760^262144+1 (Subaguru); 238109742^131072+1 (zunewantan); 8347*2^1984508+1 (H Saito); 7731*2^1984511+1 (valterc); 2167*2^1984444+1 (Gaoyf); 4739*2^1984371+1 (bparsonnet); 9433*2^1984324+1 (NerdGZ); 5233*2^1984358+1 (Grebuloner); 2427*2^1984164+1 (valterc); 9853*2^1983846+1 (Yegor001); 404646268^65536+1 (Luca); 404613798^65536+1 (skiN); 2767*2^1983922+1 (RobertCoplin); 6133*2^1983618+1 (RobertCoplin); 5741*2^1983213+1 (Michael Millerick); 235566676^131072+1 (Raduz82) Top Crunchers:Top participants by RAC | Top teams by RAC |
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