Q: Is 21,440 a Prime Number?
A: No, 21,440 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 21440 can be evenly divided by 1 2 4 5 8 10 16 20 32 40 64 67 80 134 160 268 320 335 536 670 1,072 1,340 2,144 2,680 4,288 5,360 10,720 and 21,440, with no remainder.
Since 21,440 cannot be divided by just 1 and 21,440, it is not a prime number.