What does it mean for a positive integer to be a power of a prime? I have a question that states: "If n is a positive integer, and σ(n) is prime then n is a power of a prime number." In this case σ(n) = the number of positive divisors of n.
What does it mean for a positive integer to be a power of a prime?

It means it is a prime raised to a specific power. Take for example $2$, this number is prime. It is also a prime power as it is $2^1$. Another example of a power of a prime would be $8=2^3$. The number $6$ is not a prime power as $6=2\times 3$ and $2,3$ are distinct primes.
