On 27 June 2014, 20:20:40 UTC, PrimeGrid’s Sierpinski/Riesel Base 5 Problem project eliminated k=138172 by finding the mega prime:
The prime is 1,198,185 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 54th overall. This is the largest known base 5 mega prime. 80 k's now remain in the Riesel Base 5 Problem.
The discovery was made by Walter Darimont (Walter Darimont) of Belgium using an Intel Core i7-3770 CPU @ 3.40GHz with 3.8GB RAM running Linux. This computer took about 18 hours and 25 minutes to complete the primality test using LLR. Walter is a member of the Aggie The Pew team.
The prime was verified on 28 June 2014 13:08:49 UTC, by Scott Brown (Scott Brown) of the United States using an Intel Core2 CPU 6600 @ 2.40GHz with 4 GB RAM running Microsoft Windows 7 Enterprise. This computer took about 38 hours and 32 minutes to complete the primality test using LLR. Scott is a member of the Duke University team.
For more details, please see the official announcement.