Show that if n has a primitive root and if the odd prime p divides n, then n is of the form p^j or 2p^j.
Could you please show me how to do this question? Thank you very much.
Can somebody help me out, I was thinking about a similar attempt.
If $\displaystyle n$ has a primitive root that means $\displaystyle \mathbb{Z}_n$ under addition and multiplication will be a finite field.
Thus,
$\displaystyle |\mathbb{Z}_n|=n$
That means,
$\displaystyle n=p^m$
Because finite fields are power of primes.
Apparently, I missed something. I happen to know that I am wrong because it is a well known theorem that I heard of it before. Can someone spot an error?
EDIT: I spotted my error. I was assuming $\displaystyle \phi (n)=n-1$ which is only true when it is a prime. I will now see if I can answer this question elegantly via finite fields.