PrimeGrid’s
27121 Prime Search
On 18 Nov 2020, 05:40:34 UTC, PrimeGrid’s 27121 Prime Search, through PRPNet
found the mega prime:
121*29584444+1
The prime is 2,885,208 digits long and will enter Chris Caldwell's “The Largest Known
Primes Database” (http://primes.utm.edu/primes) ranked 60th overall.
The discovery was made by James Winskill of New Zealand using an Intel Xeon(R)E5-2637 v3 CPU @ 3.50GHz with 64GB RAM, running Microsoft Windows Server
2012 R2. This computer took just under 13 hours 49 minutes to complete the primality
test using LLR. James Winskill is a member of the PrimeSearchTeam.
The prime was verified on 18 Nov 2020, 16:42:00 UTC, by an Intel(R) Core(TM) i77700K CPU @ 4.20GHz with 16 GB RAM, running Linux Gentoo. This computer took alittle over 1 hour 42 minutes to complete the primality test using LLR.
Credits for the discovery are as follows:
1.
2.
3.
4.
5.

James Winskill (New Zealand), discoverer
PrimeGrid, et al.
Srsieve, sieving program developed by Geoff Reynolds
PSieve, sieving program developed by Ken Brazier and Geoff Reynolds
LLR, primality program developed by Jean Penné

Entry in “The Largest Known Primes Database” can be found here:
https://primes.utm.edu/primes/page.php?id=131410
PrimeGrid’s 27121 Prime Search was originally a collaboration with the 12121 Search,which was established on 24 May 2004 to search for large primes of the form 121*2^n1. Later, on 1 Mar 2005, they added k=27 to their search. PrimeGrid added the +1 formand searches both k’s and forms together.
Using a single PC would have taken years to find this prime. So this timely discovery
would not have been possible without the thousands of volunteers who contributed
their spare CPU cycles. A special thanks to everyone who contributed their advice
and/or computing power to the search - especially all the sievers who work behind thescenes to make a find like this possible.
The 27121 Prime Search will continue to seek even larger primes. To join the searchplease visit PrimeGrid: http://www.primegrid.com

PrimeGrid’s
27121 Prime Search
About PrimeGrid
PrimeGrid is a distributed computing project, developed by Rytis Slatkevičius andcurrently managed by Tyler Bredl, Scott Brown, Ulrich Fries, Michael Goetz, MichaelGutierrez, Dao Heng Liu, Reginald McLean, Rytis Slatkevičius, Roman Trunov, andChristian Wallbaum.
PrimeGrid utilizes BOINC and PRPNet to search for primes with the primary goal ofbringing the excitement of prime finding to the "everyday" computer user. Simply
download the software and let your computer do the rest. Participants can choose froma variety of prime forms to search. With a little patience, you may find a large or evenrecord-breaking prime.
BOINCThe Berkeley Open Infrastructure for Network Computing (BOINC) is a software
platform for distributed computing using volunteered computer resources. It
allows users to participate in multiple distributed computing projects through asingle program. Currently BOINC is being developed by a team based at theUniversity of California, Berkeley led by David Anderson.
This platform currently supports projects from biology to math to astronomy. For
more information, please visit BOINC: http://boinc.berkeley.edu
PRPNet
PRPNet is a client/server application written by Mark Rodenkirch that is
specifically designed to help find prime numbers of various forms. It is easily
ported between various OS/hardware combinations. PRPNet does not run each
PRP test itself, but relies on helper programs, such as LLR, PFGW, phrot, wwww,and genefer to do the work.
For more information, please visit PrimeGrid’s PRPNet forum thread:
http://www.primegrid.com/forum_thread.php?id=1215
For more information about PrimeGrid and a complete list of available prime search
projects, please visit: http://www.primegrid.com