Q: Is 721,636 a Prime Number?
A: No, 721,636 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 721636 can be evenly divided by 1 2 4 29 58 116 6,221 12,442 24,884 180,409 360,818 and 721,636, with no remainder.
Since 721,636 cannot be divided by just 1 and 721,636, it is not a prime number.