Q: Is 21,087 a Prime Number?
A: No, 21,087 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 21087 can be evenly divided by 1 3 9 11 27 33 71 99 213 297 639 781 1,917 2,343 7,029 and 21,087, with no remainder.
Since 21,087 cannot be divided by just 1 and 21,087, it is not a prime number.