title: If a 32-bit integer overflows, can we use a 40-bit structure instead of a 64-bit long one?
body: <p>If, say, a 32-bit integer is overflowing, instead of upgrading <code>int</code> to <code>long</code>, can we make use of some 40-bit type if we need a range only within 2<sup>40</sup>, so that we save 24 (64-40) bits for every integer?</p>
  
  <p>If so, how?</p>
  
  <p>I have to deal with billions and space is a bigger constraint.</p>