a square number has an odd number of factors. A prime number has only two factors - the number itself and 1. Square numbers are formed by multiplying a number by itself. All square numbers have an ...

Prime numbers are special numbers, greater than 1, that have exactly two factors, themselves and 1. 19 is a prime number. It can only be divided by 1 and 19. 9 is not a prime number. It can be ...