title: What to do when you need to store a (very) large number?
body: <p>I am trying to do a <a href="https://projecteuler.net/problems" rel="nofollow noreferrer">Project Euler</a> problem but it involves adding the digits of a very large number. (100!)</p>
  
  <p>Using Java int and long are too small. </p>
  
  <p>Thanks for any suggestions</p>