Q: Is 21,723 a Prime Number?
A: No, 21,723 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 21723 can be evenly divided by 1 3 13 39 557 1,671 7,241 and 21,723, with no remainder.
Since 21,723 cannot be divided by just 1 and 21,723, it is not a prime number.