Six of them.
Four
All of them. Different numbers have different numbers of factors.
The limit is infinity if the factors do not have to be whole numbers. If you stipulate that the factors have to be whole numbers, then, yes, for each number, there is a limit to how many factors it has. For example, the number 4 has only 3 whole-number factors: 1, 2, and 4.
Four of them.
1,2,4,8,16, so 5
Six numbers. They are 1, 2, 4, 5, 10 and 20.
There are infinitely many such numbers.
14 (I think).
Four: 1 5 25 125.
A whole number has an odd number of unique factors if and only if it is a perfect square. The perfect squares less than 10 are 0, 1, 4, and 9. Therefore, there are four whole numbers less than 10 that have an odd number of unique factors.
12 does not have any factors under 1, factors are whole numbers.
Its factors are: 1, 2, 4 and 8 which makes four of them