The number zero is not a prime number. By definition, a prime number dictates that the number must be a whole number greater in value than one and must be divisible by only itself and one.
Yes, 2 is a prime number. In fact, 2 is the only even number that is prime. A prime number is a number that has only two factors, the number 1 and itself.
The number 1 is not a prime number. A prime number by definition is a positive integer greater than 1 that is evenly divisible by only itself and 1.
Two is a prime number. Two is the smallest prime number and the only even prime number, since all other even numbers divide by two.
Seven is a prime number. A prime number is a positive number that only has two possible divisible numbers. A prime number can only be divided by one and itself. The number 7 can only be divided by 1 or 7, and no other number equally divides it.
Fifteen is not a prime number. A prime number is a positive number that has only two possible divisors, 1 and itself. Fifteen can be divided by 3 and 5 as well as 1 and itself.
Nine is not a prime number. It is a composite number, because it has more than two factors. A prime number is only divisible by one and by itself, and nine is divisible by one and by nine, but it is also divisible by the number three.