Q: Is 21,403 a Prime Number?
A: No, 21,403 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 21403 can be evenly divided by 1 17 1,259 and 21,403, with no remainder.
Since 21,403 cannot be divided by just 1 and 21,403, it is not a prime number.