Let n be a pos. int. The Euler Phi-func phi(n) is defined to be the # of pos. integers not exceeding n that are relatively prime to n.

1a) Let n = 250. Find phi(n).

b.) Determine the number of primitive roots n has.

c.) Find any of these 5 primitive roots.

Okay, so my book doesn't really go over how to find phi(n), except it gives a table of phi(n) up to n = 100. And then isn't primitive root just phi(phi(n)).

I *believe* a.) is 100, although not sure how to show it, and then therefore b.) will be 40, although showing it is the issue. Probably the hardest part is c.)