Q: Is 21,639 a Prime Number?
A: No, 21,639 is not a prime number.
A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 21639 can be evenly divided by 1 3 7,213 and 21,639, with no remainder.
Since 21,639 cannot be divided by just 1 and 21,639, it is not a prime number.