Q: Is 399,721 a Prime Number?
A: No, 399,721 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 399721 can be evenly divided by 1 7 17 119 3,359 23,513 57,103 and 399,721, with no remainder.
Since 399,721 cannot be divided by just 1 and 399,721, it is not a prime number.