Factorial factors

Number Theory Level 4

How many integers $n$ are there such that $2\leq n\leq 100$ , and $(n-1)!$ is not divisible by $n$ ?

Details and Assumptions:

The number $n!$ , read as n factorial, is equal to the product of all positive integers less than or equal to $n$ . For example, $7! = 7 \times 6 \times 5 \times 4 \times 3 \times 2 \times 1$ .