Q: Is 391,221 a Prime Number?
A: No, 391,221 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 391221 can be evenly divided by 1 3 9 17 51 153 2,557 7,671 23,013 43,469 130,407 and 391,221, with no remainder.
Since 391,221 cannot be divided by just 1 and 391,221, it is not a prime number.