Q: Is 21,608 a Prime Number?
A: No, 21,608 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 21608 can be evenly divided by 1 2 4 8 37 73 74 146 148 292 296 584 2,701 5,402 10,804 and 21,608, with no remainder.
Since 21,608 cannot be divided by just 1 and 21,608, it is not a prime number.