Difference between a factor and a proper factor?

A factor of a whole number n is any whole number, that when multiplied by another whole number, results in n. For example, 1, 2, 3, and 6 are factors of 6. 1 is a factor, because 1*6 = 6, 2 is a factor, since 2*3= 6, etc. Another way to say this is that a whole number is a factor of n if it divides n evenly.

A proper factor of n is any factor that is not 1 or n. Using the example above, the proper factors of 6 are 2 and 3.