Q: Is 221,991 a Prime Number?
A: No, 221,991 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 221991 can be evenly divided by 1 3 7 11 21 31 33 77 93 217 231 341 651 961 1,023 2,387 2,883 6,727 7,161 10,571 20,181 31,713 73,997 and 221,991, with no remainder.
Since 221,991 cannot be divided by just 1 and 221,991, it is not a prime number.