A prime number has only two factors: 1 and itself. Acomposite number has more than two factors. Thenumber 1 is neither prime nor composite. The prime numbers between 2 and 31 are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29 and 31 since each of these numbers has only two factors, itself and 1.