Q:
# Is 21 a Prime Number?

**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.

The number 21 is what is known as a composite number, which is an integer that is evenly divisible by a positive number other than itself and one. All composite numbers can be broken down into two or more prime factors. Since 7 x 3 = 21, and 7 and 3 are both prime numbers, they are the prime factors of 21. Semiprime numbers are numbers that have only two prime factors, so 21 is a semiprime number.

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Q:
## Is 2 a Prime Number?

A: 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. Full Answer >Filed Under: -
Q:
## Is 69 a Prime Number?

A: The number 69 is not a prime number, as it has the factors of 3 and 23. A prime number is one which is only evenly divisible by itself and the number 1. Full Answer >Filed Under: -
Q:
## Is Three a Prime Number?

A: The number 3 is a prime number. A prime number is a positive number that can only be divided evenly by the number 1 and itself. Full Answer >Filed Under: -
Q:
## Is Five a Prime Number?

A: Five is a prime number. A prime number is a number which only has two factors. Those two factors are one and the number itself. Full Answer >Filed Under: