What is a prime factor of the composite number 66?

The number 66 can be broken down into the following prime factors:

• 66 ÷ 2 = 33 ÷ 3 = 11 ÷ 1 = 11

So 66 is 2 • 3 • 11 = 2 x 3 = 6 x 11 = 66.