That’s how many are in the largest prime number ever discovered, which was announced by mathematicians at the University of Central Missouri. Curtis Cooper, a computer science professor at the school, has made something of a cottage industry out of finding huge prime numbers, and this is the third record he has claimed. The latest one “took 39 days of nonstop computing on one of the university’s PCs” to find, according to a news release. Fun facts: these mega-prime numbers are called Mersenne numbers, named for a 17th century French monk; the hunt for them is called the Great Internet Mersenne Prime Search, or G.I.M.P.S. And according to The Associated Press, anyone who can come up with one that has 100 million digits could win $150,000 from the Electronic Frontier Foundation.