23 is prime. And, for your information, a nun is a Christian woman who dedicates her life to her religion and has nothing whatsoever to do with prime numbers.
None of them is a prime number.
None of them are prime numbers
There are none
23 is prime.
The prime number is 24
19. It is prime.
You can work this out, Prime numbers can only be divided by themselves or 1. Therefore as 20 can be divided by 2 it it not prime. The same is true for 22 and 24. Thus the prime must be either 21 or 23. See if either of these numbers can be divided by 7, if it can then the prime must be the other number.
21
Do you mean, "What is the prime factorization of 21?"
21 is not prime.
38
21