The factors of the number 23 are 23 and 1. Factors of a number are the numbers that are multiplied together to equal the given number.
A prime number is any positive number that is only divisible evenly by itself and the number one. Since the number 23 only has two factors, itself and one, it is a prime number.
A prime number only refers to whole numbers, not decimals or fractions. If a positive number is not a prime number, it is a composite number. A composite number has at least one additional divisor other than the number one and itself.