16 and 81 have 5 factors
625 has five factors.
The numbers between 10 and 30 that have exactly 5 factors are 16 and 25. The number 16 has factors 1, 2, 4, 8, and 16. The number 25 has factors 1, 5, 25, but since it is a perfect square, it also includes the repeated factor of 5. These are the only two numbers between 10 and 30 that have exactly 5 factors.
625 has five factors.16 does, among others.
Indeed, the number 16 has 5 factors, 1, 2, 4, 8, and 16.
A prime number, like 2, 3 or 5.
16
16
16 does.
16
A prime number has exactly two factors.
16
Any number with five factors is composite. There isn't one in that range.