21 is composite number that is a multiple of 3. 31 is a prime number.
31 and 61 are prime, the rest composite.
21 is composite as 3 times 7 is 21 31 is prime
The only composite factor of 21 is 21.
21 is a composite number
The composite numbers between 21 and 31 are: 21 22 24 25 26 27 28 30
Not necessarily. For example 15 and 16 are composite numbers. They add to 31, which is a prime number. Similarly, the composite numbers 20 and 21 add up to 41, which is a prime number.
21 is divisible by 3 and 7, so it is composite. 91 is divisible by 7 and 13, so it is composite. 51 is divisible by 3 and 17. 31 is divisible by only 1 and itself, so it is the prime number.
A composite number is a number that has more than two factors. The factors of 21 are 1, 3, 7, and 21. Therefore, 21 is a composite number.
The next composite number after 20 is 21.
21 is composite.
93 is composite.