Q: Is 21,128 a Prime Number?
A: No, 21,128 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 21128 can be evenly divided by 1 2 4 8 19 38 76 139 152 278 556 1,112 2,641 5,282 10,564 and 21,128, with no remainder.
Since 21,128 cannot be divided by just 1 and 21,128, it is not a prime number.