>>7
lol.

Totients are weird, I've only seen them used in crypto stuff, like generating keys for RSA.
At first I was trying to figure out how to generate the series of highly totient numbers (http://www.research.att.com/~njas/sequences/A097942) but my maths and Haskell skills just aren't good enough, so I just settled on being satisfied that I managed to get the cototient function to work right.