For years, a French mathematician searched for a proof that a gigantic number is prime. His method is still used 150 years ...

Update, Jan. 4, 2018: On Wednesday, the Great Internet Mersenne Prime Search announced that a computer owned by Jonathan Pace in Germantown, Tennessee, discovered a new prime number. At 23,249,425 ...

The record number, nicknamed M74207281, has more than 20 million digits. That's nearly 5 million digits longer than the previous record. If you printed each digit 1 mm wide, the number would stretch ...