New largest prime number discovered

Washington, Jan 21: A computer has helped scientists discover the largest prime number ever with over 22 million digits, breaking the previous record by approximately 5 million digits.

A team at the University of Central Missouri, headed by Curtis Cooper also held the old record, they have actually broken the record four times.

Cooper and his team are part of the The Great Internet Mersenne Prime Search (GIMPS) collaboration, an effort by a lot of volunteers to find ever larger prime numbers - or, more specifically, a particular class of prime numbers that are called Mersenne, where it is one less than a power of two.

Cooper said he was notified by an email sent by the software running on a personal computer (PC) that the prime number, written as 2@74,207,281 - 1, had been found.

The find came after a month of number crunching on a single Intel based PC. Interestingly, the PC tried to notify Cooper and his team about the find back in September last year, but a glitch prevented it from being sent.

It was only during a maintenance cycle that the message reporting the prime number found, was sent. The official discovery date is January 7th, 'Phys.org' reported.

The search for new and bigger prime numbers is conducted using software developed by the GIMPS team, called prime95 - it grinds away, day after day, until a new prime number is found.

While the numbers that it finds are of interest, they no longer serve much of any practical use, the software has been used for other purposes though - it has found flaws in Intel CPUs, for example.

The new prime number has been named M74207281 and the team says that it was "calculated by multiplying together 74,207,281 twos then subtracting one."

It has already been tested and confirmed by three different independent teams running software on different machines.

PTI