Almost three years ago, George and I talked about the discovery of what was then the largest known prime number. Back then, the newly-discovered prime was 213,466,917-1, which has 4,053,946 decimal digits.
It was reported Tuesday that a new champion prime number has emerged: 230,402,457-1. This one has over 9.1 million digits!
In both cases, the prime numbers were identified as part of the Great Internet Mersenne Prime Search, an effort involving people around the globe who contribute spare processing from their own computers.
Mersenne primes are special prime numbers which are powers of 2, minus 1. Also, the exponent is itself a prime number.