No 21 is not a Prime number because it has more than two factors therefore it is a composite number
21 is the product of two prime numbers, three and seven. A prime number is defined as a number divisible only by one or itself. So ... NO ... 21 is not a prime number.
23 is a prime number.
Only 23 is a prime number.
19 and 23 are prime.
21 x 2 does not equal 40. 21 is not a prime number.
The prime factorization of 21 is: 3 x 7
47 is a prime number 21 & 87 divisible by 3, and 4 is divisible by 2
21 is not prime.
It can be. 21 is relatively prime with 32.
The prime factorization for 21 is 3x7.
Do you mean, "What is the prime factorization of 21?"
number 21 is prime