What type of number has an odd number of factors?

Solution:

A factor of a number is a number that divides the given number evenly without leaving any remainder.

Most of the numbers have an even number of factors except for the square numbers which have an odd number of factors.

Let's take some examples to understand the number of factors

Factors of 3 = 1, 3 (2 factors)

Factors of 12 = 1, 2, 3, 4, 6, 12 (6 factors)

Factors of 15 = 1, 3, 5, 15 (4 factors)

Thus, we see that the non-square numbers have an even number of factors.

Square numbers are formed by multiplying a number by itself such as 9, 16, 25

All square numbers have an odd number of factors. 

Let's take some examples:

Factors of 9: 1, 3, 9 (3 factors)

Factors of 16: 1, 2, 4, 8, 16 (5 factors)

Factors of 25: 1, 5, 25 (3 factors)

Thus, we see that the square numbers have an odd number of factors

What type of number has an odd number of factors?

Summary:

A square number has an odd number of factors