In 1940, Hardy used the theory of numbers as an example of a profoundly and permanently useless discipline in A Mathematicians Apology[1]. The fact that number

In 1940, Hardy used the theory of numbers as an example of a profoundly and permanently useless discipline in A Mathematicians Apology[1]. The fact that number theory is the basis for modern cryptography gives the lie to this sentiment. The fact is that we don't know whether the search for Mersenne primes, or any other mathematical endeavour, will reveal anything useful, but given the depth of interconnection between different branches of mathematics and the usefulness of some of those branches, it doesn't seem plausible that we won't find useful things. Although Hardy turned out to be wrong about number theory and its applications, his arguments for the intrinsic value of the study of mathematics in the absence of any real utility stand as well. And of course, as another commenter has pointed out, making computers do things like this is a great way to develop phenomenally fast and useful algorithms. Finally, the project found a bug in Intel CPUs[2], which is kind of neat... [1] https://www.math.ualberta.ca/mss/misc/A%20Mathematician's%20Apology.pdf https://www.math.ualberta.ca/mss/misc/A%20Mathematician's%20... [2] http://www.extremetech.com/computing/220953-skylake-bug-causes-intel-chips-to-freeze-in-complex-workloads http://www.extremetech.com/computing/220953-skylake-bug-caus...