Best Answer

21 is composite number that is a multiple of 3. 31 is a prime number.

Q: Is 21 and 31 a prime number?

Write your answer...

Submit

Still have questions?

Continue Learning about Math & Arithmetic

31 is a prime number.

31

31

31 and 41 are prime numbers because they have only two factors

The prime numbers greater than 21 are 23, 29, 31, 37, 41, 43, 47, etc.

Related questions

31 is a prime number.

21 is not a prime.

31

31

31

31 is the only one that has only two factors: 1 and itself. It is the prime number.

31 and 41 are prime numbers because they have only two factors

21 = 3 * 7 31 = 31 (it is prime) 100 = 2 * 2 * 5 * 5

The prime numbers greater than 21 are 23, 29, 31, 37, 41, 43, 47, etc.

31 and 61 are prime, the rest composite.

It is: B 31 is a prime number because it has only two factors which are itself and one

31 is a prime number