Prime numbers are very special. A prime number is a number that is divisible evenly only by itself and 1. Hence, 18 is not a prime number because it can be formed as the product of 2 and 9, 3 and 6, or 18 and 1. In other words, it has many factors, other than itself and 1. In contrast, 23 is a prime number because its only factors are 1 and itself, 23. Some questions on the SHSAT will ask us to determine whether a number is, in fact, prime. To determine whether any given numb