Since the problem states that every number is a prime number, then the number must be a natural number greater than 1 that has no positive divisors other than 1 and itself.
2 / 1 = 2 OR 2 / 2 = 1 These numbers are prime numbers because their divisors 5 / 1 = 5 OR 5 / 5 = 1 are 1 and itself. 11/1 = 11 OR 11/11 = 1