**The prime factors of 84 are 7, 3 and 2.** When 7 is multiplied by 3, 2 and then 2 again, the result is the original 84.

Prime factors refer to the factors of a number that are also prime numbers. Prime numbers are the numbers that are greater than one that only have factors of themselves and 1. Dividing 84 by the smallest prime factor yields 42, which yields 21 when divided by 2 again. Finally, 21 can be divided the its smallest prime factor, 3, to yield 7, which is also a prime number.