Largest Prime Number Discovered – With More Than 23m Digits (mersenne.org)
chalsall writes: Persistence pays off. Jonathan Pace, a GIMPS volunteer for over 14 years, discovered the 50th known Mersenne prime, 2^77,232,917 -- 1 on December 26, 2017. The prime number is calculated by multiplying together 77,232,917 twos, and then subtracting one. It weighs in at 23,249,425 digits, becoming the largest prime number known to mankind. It bests the previous record prime, also discovered by GIMPS, by 910,807 digits. You can read a little more in the press release.
Serious reply in response to a decent joke: GIMPS is the Great Internet Mersenne Prime Search, which is more or less like SETI@home or Folding@home, but for Mersenne primes. I wasn't aware what it was, so I figured I'd share. Also, I had forgotten that Prime95, which is oftentimes used to stress cooling solutions in PCs, was actually created for use in finding large prime numbers, and was apparently developed by GIMPS.