Huge new prime number discovered

The search for new high prime number continues

Mathematicians in California could be in line for a $100,000 prize (£54,000) for finding a new prime number which has nearly 13 million digits.

Prime numbers can be divided only by themselves and one.

The prize was set up by the Electronic Frontier Foundation to promote co-operative computing on the internet.

The team from the University of California at Los Angeles (UCLA) found the new number by linking 75 computers and harnessing their unused power.

This enabled them to perform the enormous number of calculations needed to find and verify the new prime.

The group was searching for so-called higher "Mersenne" prime numbers - named after the 17th Century French mathematician Marin Mersenne.

Mersenne primes are expressed as two to the power of P, minus one - with P being itself a prime number. The new prime can therefore be written as 2^43,112,609 -1.

Prime numbers have long fascinated 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.

The number 10 is not prime because it is divisible by 2 and 5.

Mersenne primes have been central to number theory since they were first discussed by Euclid in 350 BC.

The Fundamental Theory of Arithmetic says they are the building blocks of numbers.

The latest discovery was made as part of the volunteer computing project known as the Great Internet Mersenne Prime Search ("GIMPS").

Only 46 Mersenne primes are currently known. The EFF prize was first offered nearly 10 years ago.