The number one is neither prime nor composite. Prime numbers are those defined as natural numbers greater than one not divisible by any other numbers but one and itself. Composite numbers have at least one additional positive divisor and include all whole numbers greate...
The number 2 is a prime number. It is the smallest prime number and the only even number that is prime. Its only two factors are 1 and 2.
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.
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.
The prime factorization of 54 is 2 x 3 x 3 x 3, which can also be written as 2 x 33. Prime factors are the prime numbers that are multiplied to get another number. A prime number is any number that can only be divided by itself and 1, such as 3, 5 and 17; numbers that c...
The number 21 is not a prime number. Prime numbers are numbers greater than one that are evenly divisible by only 1 and themselves. As the number 21 has multiple factors, including 1, 21, 3 and 7, it does not meet the definition of a prime number.
One is not a prime number because the definition of a prime number is any number that is greater than one that is only divisible by one and itself. Since one is of course not greater than one, it does not fit the definition of a prime number.