Q: Is 728,721 a Prime Number?
A: No, 728,721 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 728721 can be evenly divided by 1 3 7 9 21 43 63 129 269 301 387 807 903 1,883 2,421 2,709 5,649 11,567 16,947 34,701 80,969 104,103 242,907 and 728,721, with no remainder.
Since 728,721 cannot be divided by just 1 and 728,721, it is not a prime number.