On 25 December 2013, 11:53:21 UTC, PrimeGrid’s The Riesel Problem project eliminated k=40597 by finding the mega prime:
The prime is 2,049,571 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 22nd overall. This is the largest prime found in The Riesel Problem and PrimeGrid's 12th elimination. 52 k's now remain.
The discovery was made by Frank Meador (v149907) of the United States using an AuthenticAMD AMD Phenom(tm) 9500 Quad-Core Processor with 878 MB RAM running Linux. This computer took 29 hours 35 minutes to complete the primality test using LLR.
The prime was verified on 27 December 2013, 20:54:41 UTC, by Eliot Meadow of the United States using an Intel(R) Pentium(R) 4 CPU 2.80GHz with 2 GB RAM running Microsoft Windows XP Media Center. This computer took about 66 hours and 17 minutes to complete the primality test using LLR. Eliot is a member of the BOINCstats Team.
For more details, please see the official announcement.