A mathematician at the University of Central Missouri has discovered the largest known prime number, which has more than 17 million digits.

Prime numbers have long fascinated amateur and professional mathematicians. An integer greater than one is called a prime number if its only divisors are one and itself. The first prime numbers are 2, 3, 5, 7, 11, etc. For example, the number 10 is not prime because it is divisible by 2 and 5. A Mersenne prime is a prime number of the form 2P-1. The first Mersenne primes are 3, 7, 31, and 127 corresponding to P = 2, 3, 5, and 7 respectively. There are only 48 known Mersenne primes so far, including the one discovered on January 25th on Great Internet Mersenne Prime Search (GIMPS) volunteer Curtis Cooper's computer. Dr. Cooper is a professor at the University of Central Missouri.

The new prime number, 257,885,161-1 - 2 multiplied by itself 57,885,161 times, less one, has 17,425,170 digits.

The new prime number is a member of a special class of extremely rare prime numbers known as Mersenne primes.

To prove there were no errors in the prime discovery process, the new prime was independently verified using different programs running on different hardware.

The discovery is eligible for a $3,000 GIMPS research discovery award.