Amateurs find largest prime number yet: it's 17 million digits long

A group of amateur volunteers from Missouri has found a 17-million-digit prime number, or a natural number divisible only by one and itself.

 

But the number - 2 to the power of 57,885,161 minus 1 - is so big that a text file containing it would be 22.5 MB big.

 

Yet, it is considered a 14th consecutive victory for the Great Internet Mersenne Prime Search (GIMPS) project, tech site CNET reported.

 

Mersenne primes are named after the French monk Marin Mersenne, who investigated a particular type of prime number: 2 to the power of "p" minus one, in which "p" is an ordinary prime number.

 

The discoverer of the latest prime number is Curtis Cooper, a professor at the University of Central Missouri who runs the prime-hunting software on a network of computers.

 

Cooper's find is the 48th Mersenne prime so far discovered. GIMPS said it has so far found the 14 largest Mersenne primes, CNET said.

 

Also, Cooper had found record primes in 2005 and 2006, it added.

 

Those who are curious about the full number can view it here.

 

GIMPS is a project that searches for prime numbers using thousands of independent computers. It announced the find after verifying it.

 

Presently, GIMPS involves 98,980 people and 574 teams with 730,562 processors performing some 129 trillion calculations per second.

 

Practical use for prime numbers

 

Although they were once considered just mathematical curiosities, prime numbers are important to encrypted communications, CNET said.

The longer the prime number used to encrypt a message, the more difficult it is to break. This makes prime numbers valuable to businesses, and the longer the better.  

Prizes

 

Cooper won a $3,000 prize for his effort, though discovering Mersenne primes cannot be considered a get-rich-quick scheme.

 

On the other hand, the Electronic Frontier Foundation is offering $150,000 to the discoverer of the first prime number with at least 100 million digits.

 

"It's already awarded prizes for primes 1-million and 10-million digits, and it's got a $250,000 prize queued up for a billion-digit prime," CNET said.

 

Bigger numbers

 

In 1998, GIMPS found 2^3021377-1, a number 909,526 digits long. In 2001, it found the 39th Mersenne prime, a number 4,053,946 digits long.

 

The 43rd Mersenne prime, which Cooper's effort found, is a 9,152,052-digit number.

 

Searching for prime numbers can be split across countless computers through distributed computing.

 

But some chores can be run on closely independent computing nodes connected by a high-speed network, and others cannot be broken down into parallel tasks at all.

 

Also, CNET said a computer-science idea called Amdahl's Law, named after mainframe computer designer Gene Amdahl, shows the limits of parallel computation.

 

"If some portion of a computer program can't be sped up by parallel processing, at a certain point throwing more processors at the problem will stop producing any speedup in the computation," it said. — TJD, GMA News