science · 24 August 1997 · 28 years ago
In 1997, Gordon Spence discovered the largest known prime number, 2^2976221 - 1, the 36th known Mersenne prime number. It took his 100-MHz Pentium PC fifteen days to prove it. At 895,932 digits in length, if printed out the number would stretch for 1.4 miles or if spoken 8 hours a day would take 28 days to complete.