Prove that for $n\in\Bbb{Z}^+$, $n$ has an odd number of positive divisors if and only if $n$ is the square of an integer.

Question

Actually I am a new student of discrete mathematics and this question is weird for me. Can anyone help me?

I think that here we will use the theorem that every integer is written in the form of product of primes and then we argue by saying that it is a square because for divisors to be odd the power of primes must be even or something like that. Can you guys please help me out! Using number theory