15 is composite number 17, 19 and 23 are prime numbers.
21
the composite number is 23
18 (All even numbers except 2 are composite.)
15 has more than exactly two factors (1, 3, 5, and 15), therefore it is composite. 17, 19, and 23 each have exactly 2 factors (1 and the number itself), so they are primes.
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. 19 and 23 are prime.
No, the numbers 19, 21, and 23 are not composite numbers. A composite number is a positive integer greater than 1 that has more than two distinct positive divisors. In the case of these numbers, 19 and 23 are prime numbers because they are only divisible by 1 and themselves, while 21 is a composite number because it has divisors other than 1 and itself (3 and 7).
15 is composite number 17, 19 and 23 are prime numbers.
21, 55, 77, and 93 are composite numbers. 23 is a prime.
All the numbers are composite except the ones in bold: 18 19 20 21 22 23 24 25.
17, 19, 23, 29 and 31 are prime. 15, 21, 25 and 27 are composite..
19 and 23 are prime.
21
21
the composite number is 23
18 (All even numbers except 2 are composite.)