theres only one even Prime number, thats 2
prime numbers can only be divided by themselves, and 1
21, divisible by 3 or 7, so no
28 even number other than 2, so no
15, divisible by 3 or 5, so no
17 divisible only by itself and 1, so yes
28, even number, other than 2, so no
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The prime numbers between 10 and 21 are 11, 13, 17, and 19.
Four. The prime numbers between 10 and 21 are 11, 13, 17, and 19.
3, 13, 17, 23 are prime numbers. The others are not.
ANSWER: 9, 15, 21 are not prime numbers because these numbers have factors other than 1 and themselves. Therefore, 9, 15, 21 are composite numbersFactors of 9 other 1 and itself (9) : 3Factors of 15 other 1 and itself (15): 3, 5Factors of 21 other 1 and itself (21): 3, 7
17, 19, 23, 29 and 31 are prime. 15, 21, 25 and 27 are composite..