Q: Is 721,428 a Prime Number?
A: No, 721,428 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 721428 can be evenly divided by 1 2 3 4 6 12 79 158 237 316 474 761 948 1,522 2,283 3,044 4,566 9,132 60,119 120,238 180,357 240,476 360,714 and 721,428, with no remainder.
Since 721,428 cannot be divided by just 1 and 721,428, it is not a prime number.