This past week, Curtis Cooper discovered the largest-known prime number...it has 17,425,170 digits. If written down, you would need 4,647 pages, with 75 digits per line and 50 lines per page.
Cooper, a computer scientist at the University of Central Missouri, discovered the new prime number using a university computer. It took 39 days of nonstop computing.
An odd thing...this is the third large prime number discovered by Cooper. He participates as part of the Great Internet Mersenne Prime Search (GIMPS).
A Mersenne Prime is a prime number of the form 2n-1, where n is assumed to be a prime number. In Cooper's discovery, the new Mersenne prime is 257,885,161-1.
Thaks to GIMPS, a total of 48 Mersenne Primes are known. Prior to last week, the most recently discovered 47th Mersenne prime was found in June, 2009; however, it actually was smaller than the largest Mersenne Prime known at the time, which was the 45th to be discovered.
So, how can you earn the $1,000,000? The Electronic Frontier Foundation has offered prizes to people who discover Mersenne Primes: $50,000 for the first million-digit prime, $100,000 for the first ten-million-digit prime, $150,000 for the first hundred-million-digit prime, and $1,000,000 for the first billion-digit prime.
From the looks of things, this contest will not finish in our lifetime (or Cooper's)... unless, a new prime testing algorithm is created!