3, 7, and 19 have only two factors, 1 and itself. They are prime numbers.
21 has more than 2 factors: 1, 3, 7, and 21. It is a composite number.
No, they are three numbers, not one. 21 is composite.
21 is composite.
19 and 23 are prime numbers whereas 21 is a composite number
19 is prime number. 10, 21 and 62 are composite numbers.
19 is a prime number. Its only factors are 1 and 19. 21 is a composite number. Its factors are 1, 3, 7, and 21. 23 is a prime number. Its only factors are 1 and 23.
21 is composite number because it has more than one number that goes into it
21 is composite. 19 and 23 are prime.
The only composite factor of 21 is 21.
One is prime, the other two are composite.
21 is a composite number
21 is a Composite Number. A prime number is a whole number that only has two factors which are itself and one. A composite number has factors in addition to one and itself. 21 is divisible by 3 and 7.
21 is a composite number because it has at least one positive factor other than one or itself.