Q: Is 721,645 a Prime Number?
A: No, 721,645 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 721645 can be evenly divided by 1 5 101 505 1,429 7,145 144,329 and 721,645, with no remainder.
Since 721,645 cannot be divided by just 1 and 721,645, it is not a prime number.