The largest prime number yet has been discovered — and it's 17,425,170 digits long. The new prime number crushes the last one discovered in 2008, which was a paltry 12,978,189 digits long.

The number — 2 raised to the 57,885,161 power minus 1 — was discovered by University of Central Missouri mathematician Curtis Cooper as part of a giant network of volunteer computers devoted to finding primes, similar to projects like SETI@Home, which downloads and analyzes radio telescope data in the Search for Extraterrestrial Intelligence (SETI). The network, called the Great Internet Mersenne Prime Search (GIMPS) harnesses about 360,000 processors operating at 150 trillion calculations per second. This is the third prime number discovered by Cooper.

"It's analogous to climbing Mt. Everest," said George Woltman, the retired, Orlando, Fla.-based computer scientist who created GIMPS. "People enjoy it for the challenge of the discovery of finding something that's never been known before."

In addition, the number is the 48th example of a rare class of primes called Mersenne Primes. Mersenne primes take the form of 2 raised to the power of a prime number minus 1. Since they were first described by French monk Marin Mersenne 350 years ago, only 48 of these elusive numbers have been found, including the most recent discovery. [The Most Massive Numbers in the Universe]

After the prime was discovered, it was double-checked by several other researchers using other computers.

While the intuitive way to search for primes would be to divide every potential candidate by ever single number smaller than itself, that would be extremely time-consuming, Woltman told LiveScience.

"If you were to do it that way it would take longer than the age of the universe," he said.

Instead, mathematicians have devised a much cleverer strategy, that dramatically reduces the time to find primes. That method uses a formula to check much fewer numbers.

The new discovery makes Cooper eligible for a $3,000 GIMPS research discovery award.

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6 Comments

1. 1. gs_chandy 10:36 AM 2/6/13

   Surely the title should have read: "Largest prime number YET discovered" ??
   
   OK, you could even have:
   "Largest prime number YET discovered!!!" ??
   
   The way you have it, we get the impression that no larger primes will EVER be discovered, which is most unlikely, seeing that there can be no largest prime.
   
   --- GSC

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2. 2. lamorpa in reply to gs_chandy 11:59 AM 2/6/13

   And it was discovered on the last day of his life! (yet)

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3. 3. diandted 03:32 PM 2/6/13

   "Largest" prime he'll ever know about if truly deceased!!

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4. 4. gs_chandy in reply to lamorpa 08:44 PM 2/6/13

   Thank you, lamorpa and diandted...
   
   For him, it was indeed "THE LARGEST PRIME EVER DISCOVERED!"
   
   --- GSC

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5. 5. gs_chandy 08:54 PM 2/6/13

   Rather, I should have written:
   "THE LARGEST PRIME EVER, DISCOVERED!"
   
   (I had not realized that he had passed away after the discovery. If this is correct, it's remarkable indeed, perhaps even worthy of a mention in Ripley's).
   
   -- GSC

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6. 6. blk1958 09:05 PM 2/13/13

   gs_chandy, I'm certain lampora was joking while lampooning the use of "yet". I laughed. Perhaps I shouldn't have.
   

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