It is: 21 because it has more than two factors
The numbers 13 and 29 are prime - the one composite number in that list is 27.
27 is not a prime number.
29 is a prime. 9, 21, and 27 are composites because they are multiples of 3.
21 is not a prime number because it is 3 x 7
29 is prime.
27
From 10 to 30, there are 21 numbers.Six of them are prime numbers: 11, 13, 17, 19, 23, and 29.If you pick a number at random from 10 to 30, the probabilitythat it's a prime number is6/21 = 2/7 = 28.57% (rounded)
The prime numbers greater than 21 are 23, 29, 31, 37, 41, 43, 47, etc.
prime numbers above 13 = 17, 19, 23, 29, 31,...
39 is not a prime number. It can be divided by 3 and 13.
39 is not prime. Its factors are 3 and 13.
27