Q: Is 21,915 a Prime Number?
A: No, 21,915 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 21915 can be evenly divided by 1 3 5 9 15 45 487 1,461 2,435 4,383 7,305 and 21,915, with no remainder.
Since 21,915 cannot be divided by just 1 and 21,915, it is not a prime number.