Q: Is 21,351 a Prime Number?
A: No, 21,351 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 21351 can be evenly divided by 1 3 11 33 647 1,941 7,117 and 21,351, with no remainder.
Since 21,351 cannot be divided by just 1 and 21,351, it is not a prime number.