Q: Is 21,357 a Prime Number?
A: No, 21,357 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 21357 can be evenly divided by 1 3 7 9 21 27 63 113 189 339 791 1,017 2,373 3,051 7,119 and 21,357, with no remainder.
Since 21,357 cannot be divided by just 1 and 21,357, it is not a prime number.