21 is divisible by the prime number 3 which results in 7. The result 7 cannot be divided any further as it is a prime number. Hence the prime factors of 21 are 3, 7.
21 is divisible by the prime number 3 which results in 7. The result 7 cannot be divided any further as it is a prime number. Hence the prime factors of 21 are 3, 7.