6 8 9 10 12 14 15 16
Chat with our AI personalities
15 is a composite number - it can be divided by 3 and 5. 11, 13, 17 and 19 are all prime numbers, not composite.
85 is a composite number because numbers other then 1 and itself equally go into it. 5 x 17 = 85, so 5 and 17 both go into 85 making it a composite number. (All numbers ending in 5 are composite, because 5 goes into them.)
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31 are prime numbers. they are not composite numbers.
There are nine (9): 2, 3, 5, 7, 11, 13, 17, 19, 23.
5, 11 and 17 are prime number but 9 and 27 are composite numbers