On 8 January 2022, 20:46:05 UTC, PrimeGrid’s 321 Prime Search found the Mega Prime:
The prime is 5,477,722 digits long and has entered Chris Caldwell's “The Largest Known Primes Database” ranked 20th overall.
The discovery was made by an anonymous user of Poland using an Intel(R) Core(TM) i9-9900K CPU @ 3.60GHz with 32GB RAM, running Microsoft Windows 10 Professional x64 edition. This computer took about 2 hours, 40 minutes to complete the primality test using LLR2.
For more details, please see the official announcement.