On 29 February 2016 05:39:14 UTC, PrimeGrid’s Sophie Germain Prime Search found a World Record Sophie Germain prime: 2618163402417*2^1290000-1 (2 p +1: 2618163402417*2^1290001-1 ) The prime is 388,342 digits long, eclipsing the previous record of 200,701 digits. It enters Chris Caldwell's “ The Largest Known Primes Database ” ranked 1st for Sophie Germain primes and 3,747th overall. The discovery was made by Scott Brown ( Scott Brown ) of the United States using an Intel(R) Core(TM)2 Quad CPU Q6700 @ 2.66GHz with 4 GB RAM running Microsoft Windows 7 Enterprise. This computer, using LLR, took about 1 hour and 33 minutes to complete the primality test. Scott is a member of the Duke University team. The prime was verified on 29 February 2016 06:21:47 UTC, by Vaughan Davies ( vaughan ) of Australia using an Intel(R) Core(TM) i7-4770S CPU @ 3.10GHz with 32 GB RAM running Microsoft Windows 7 Ultimate. This computer, using LLR, took about 47 minutes to complete the primality test. Vaughan is a member of the AMD Users team. For more details, please see the official announcement .

A couple of fun facts to add: The last world record Sophie Germain prime that was found by PrimeGrid in 2012 was also found by a user from the United States and verified by a user from Australia. The announcement for the last SGS world record was also my first official announcement post here after taking over that task from John ! Time sure does fly when you are having fun. :)

Congratulations Scott! This is really a great discovery. That sounds so low key. On the day Scott found that prime, I was all exclamation marks and ALL CAPS on the admin back-channels. :) Mega primes may have become routine (there were 6 last month, and 2 so far this month), but an SGS or twin is really rare. ____________ My lucky number is 75898 524288 +1