27 and 31 are prime.
31, since it is prime (the rest are composite).
31 is prime.
It is a prime.
31 is prime.
31 is a prime number
31 is prime.
Composite. Its prime factors are 23 and 31.
31 is a prime number.
961 is not prime. 961 = 31 * 31
31 is a prime number
39 is a composite number 1 is neither prime nor composite number 31 and 41 are prime numbers.
No, it is a prime number.