Big News in Numbers
A mathematician discovers a record-breaking prime number with the aid of computers
Curtis Cooper, a professor at the University of Central Missouri, likened his discovery to climbing Mt. Everest. (Bryan Tebbenkamp, UCM Photo Services)
The world’s largest known prime number was recently discovered—and it seems to never end! The number—2 raised to the 57,885,161 power minus 1 (257,885,161-1)—is a whopping 17,425,170 digits long. It shatters the previous record for a prime number. Discovered in 2008, that number has only about 13 million digits.
A prime number is a whole number (other than 0 and 1) that can be divided only by itself and 1 without a remainder. For example, 2 is a prime number because it can only be divided by 2 and 1. The next four prime numbers are 3, 5, 7, and 11.
Mathematician Curtis Cooper, a professor at the University of Central Missouri (UCM), discovered the new prime.
“I kind of consider it like climbing Mount Everest or finding a really rare diamond or landing somebody on the moon,” says Cooper. “It’s an accomplishment. It’s a scientific feat.”
Cooper used a huge network of computers devoted to finding prime numbers. The network, called the Great Internet Mersenne Prime Search (GIMPS), includes about 360,000 computers that operate at 150 trillion calculations per second. It took 1,000 UCM computers—working nonstop—39 days to make the discovery.
“Because the numbers are becoming larger with each discovery, it is anticipated that future discoveries will take longer,” says Cooper.
But the hunt continues for an even larger prime. The Electronic Frontier Foundation is offering a $150,000 prize to the person who discovers the first prime number with at least 100 million digits.
The new number is one of 48 rare primes called Mersenne primes. These take the form of 2 raised to the power of a prime number minus 1. Only 48 Mersenne primes currently exist, including the new discovery.
GIMPS, created in 1996 by American computer scientist George Woltman, found the previous 14 Mersenne primes. The network uses software that allows the huge network of computers to search for the numbers and automatically report their findings.
What if you wanted to search for primes the old-fashioned way? You’d be hunting for quite a while! You would need to divide every single potential prime number by every single number smaller than itself.
“If you were to do it that way,” Woltman told LiveScience, “it would take longer than the age of the universe.”