On 13 August 2020, 17:09:10 UTC, PrimeGrid’s Sierpinski/Riesel Base 5 Problem project eliminated k=109838 by finding the mega prime:
The prime is 2,214,945 digits long and enters Chris Caldwell's “The Largest Known Primes Database” ranked 72ns overall and is the largest known base 5 prime. 62 k’s now remain in the Riesel Base 5 problem.
The discovery was made by Erik Veit (zombie67 [MM]) of the United States AMD Ryzen Threadripper 3970X 32-Core Processor with 63GB RAM, running Linux Mint. This computer took about 6 hours, 14 minutes to complete the primality test using LLR. Erik Veit is a member of the SETI.USA team.
The prime was verified on 13 August 2020, 22:53:05 UTC by Frederik Schiøler (Soulfly) of Denmark using an Intel(R) Xeon(R) Gold 6140 CPU @ 2.30GHz with 1GB RAM, running Linux Ubuntu. This computer took about 11 hours, 52 minutes to complete the primality test using LLR. Frederik Schiøler is a member of the Antarctic Crunchers team.
For more details, please see the official announcement.