Q: Is 643,420 a Prime Number?
A: No, 643,420 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 643420 can be evenly divided by 1 2 4 5 10 20 53 106 212 265 530 607 1,060 1,214 2,428 3,035 6,070 12,140 32,171 64,342 128,684 160,855 321,710 and 643,420, with no remainder.
Since 643,420 cannot be divided by just 1 and 643,420, it is not a prime number.