Q: Is 21,705 a Prime Number?
A: No, 21,705 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 21705 can be evenly divided by 1 3 5 15 1,447 4,341 7,235 and 21,705, with no remainder.
Since 21,705 cannot be divided by just 1 and 21,705, it is not a prime number.