Primes that can be written as one less than a power of two, i.e 2^n – 1 for some n, are known as Mersenne primes after the French monk Marin Mersenne who investigated their properties 350 years ago. They are the easiest large primes to find since they provide numbers to aim for, and there’s a quick way to test they are prime.
This new prime - which can be described as two raised to the power of 74,207,281 minus one - was discovered as part of the Great Internet Mersenne Prime Search, a project that over the past 20 years has connected thousands of computers around the world with the aim of hunting down prime numbers.
Large prime numbers are important in computer encryption and help make sure that online banking, shopping and private messaging are secure, but current encryption typically uses prime numbers that are hundreds of digits long, not millions.
"This prime is too large to currently be of practical value," the Gimps project admitted in a statement.
However, searching for large primes is intensive work for computer processors and can have unexpected benefits.