On 23 June 2012, 7:58:18 UTC, PrimeGrid’s The Riesel Problem project eliminated k=252191 by finding the mega prime: 252191*2^5497878-1 The prime is 1,655,032 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 21st overall. This is the largest prime found in The Riesel Problem and PrimeGrid's 9th elimination. 55 k's now remain. The discovery was made by Jan Haller (Janita) of Germany using an Intel Pentium Dual-Core E5400 @ 2.70GHz with 4 GB RAM running Windows 7. This computer took over 17 hours 30 minutes to complete the primality test using LLR. The prime was verified on 23 June 2012, 15:35:21 UTC, by Tony Gott (bayanne) of the United Kingdom. Tony is a member of the Ars Technica team. For more details, please see the official announcement.

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