Q: Is 21,643 a Prime Number?
A: No, 21,643 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 21643 can be evenly divided by 1 23 941 and 21,643, with no remainder.
Since 21,643 cannot be divided by just 1 and 21,643, it is not a prime number.