Q: Is 21,456 a Prime Number?
A: No, 21,456 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 21456 can be evenly divided by 1 2 3 4 6 8 9 12 16 18 24 36 48 72 144 149 298 447 596 894 1,192 1,341 1,788 2,384 2,682 3,576 5,364 7,152 10,728 and 21,456, with no remainder.
Since 21,456 cannot be divided by just 1 and 21,456, it is not a prime number.