What two number when multiplied equals 21 (twenty one)?
From the aboves multiple we can see that 21 is a multiple of 4 numbers.
The numbers are 1, 3, 7, 21
These numbers are called the factors of 21.
3 x 7= 21
A prime number is a number that is divisible only by 1 and itself (without a remainder).
21 is not a prime number because it is divisible by other number than 1 and itself.
Lets learn factorization of other numbers.