Who says it is? 21 is a composite number!
number 21 is prime
21 is a composite number, not a prime, having prime factors 3x7.
There is an infinite number of prime numbers that are greater than 21. The next prime number after 21 is 23.
21 is the product of two prime numbers, three and seven. A prime number is defined as a number divisible only by one or itself. So ... NO ... 21 is not a prime number.
21 is composite number that is a multiple of 3. 31 is a prime number.
number 21 is prime
21 is a composite number, not a prime, having prime factors 3x7.
There is an infinite number of prime numbers that are greater than 21. The next prime number after 21 is 23.
21 is the product of two prime numbers, three and seven. A prime number is defined as a number divisible only by one or itself. So ... NO ... 21 is not a prime number.
A prime number is any integer evenly divisible by only itself, and the number 1. Since 21 is divisible by 3 and 7, it is a composite number, not a prime number.No, 21 is not a prime number.21 is divisible by 1, 3, 7, & 21No. 21=3*7
21 is composite number that is a multiple of 3. 31 is a prime number.
3 * 7 = 21 21 is not prime
No. The only factors of a prime number are 1 and itself. The only way that 21 could be a factor of a prime number is if it were a prime number, but it is not because 21 is also divisible by 3 and 7.
21 is a composite number
no, 21*21=441