An integer (greater than one) is prime if the only whole numbers it can be divided by (without a remainder) are itself and one. All other integers are composite. In other words, a prime number has only two positive factors. Composite numbers have more. For example, seven is a prime number because its only positive factors are one and seven. Fifteen is composite because it has four: one, three, five, and fifteen.
You are here: / / Prime Numbers