Factor Questions?

Question

What numbers have 5 factors,3 factors and 9 factors.
Fastest and Correct & Detailed answer wins for best answer.

Answer 1

Most numbers have an even number of factors.
For example:
24 --> 1, 2, 3, 4, 6, 8, 12, 24

Notice how the smallest factor always matches the largest factor, the next smallest matches the next highest, etc.
1 x 24, 2 x 12, 3 x 8, 4 x 6 all equal 24.

So how do you get an *odd* number of factors? You have to have a number that is a square so that the middle factor "matches" with itself. For example:

4 --> 1, 2, 4 (3 factors)
9 --> 1, 3, 9 (3 factors)
16 --> 1, 2, 4, 8, 16 (5 factors)
25 --> 1, 5, 25 (3 factors)
36 --> 1, 2, 3, 4, 6, 9, 12, 18, 36 (9 factors)
49 --> 1, 7, 49 (3 factors)
etc.

Anyway, you get the idea and can take it from here.