31 and 61 are prime, the rest composite.
Composite
3 * 7 = 21 21 is not prime
21 is a composite number because it has more than two factors
A prime number has only 2 factors which are 1 and itself. Composite numbers are everything else except 1 and 0. 1 and 0 are neither prime, nor composite. 21 is composite.
21 is a composite number. A prime number has only 2 factors which are 1 and itself. Composite numbers are everything else except 1 and 0. 1 and 0 are neither prime, nor composite.
21 is a composite number. A prime number has only 2 factors which are 1 and itself. Composite numbers are everything else except 1 and 0. 1 and 0 are neither prime, nor composite.
A prime number has only 2 factors which are 1 and itself. Composite numbers are everything else except 1 and 0. 1 and 0 are neither prime, nor composite. 21 is composite.
1 is not composite or prime.
21 is composite
21 is composite.
21 is composite.
composite because it has more than two factors.