# A number with three of more factors?

There are many of these. Some are 4,10,15,20,25,30,35 They are called composite numbers.

### What is an abundant number?

There are three equivalent definitions for an abundant number. A number is abundant if: the sum of all its factors (including itself) is more than double the number; the sum of all factors of the number which are smaller than the number, must be more than the number; the sum of all proper factors of the number must be at least as large as the number.

### Can you Compare the number of factors of a prime number to the number of factors of a square number?

### What is a number between 12 and 40 that has three factors?

Square numbers have an odd number of factors. Other numbers have an even number of factors. The squares between 12 and 40 include 16, 25, and 36. If the number has only three factors, it must be the square of a prime number, since two of the factors will be 1 and itself, so if there is only one more factor, this third number cannot have factors itself. This means the number must be 25…