Q: Is 643,660 a Prime Number?
A: No, 643,660 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 643660 can be evenly divided by 1 2 4 5 10 20 32,183 64,366 128,732 160,915 321,830 and 643,660, with no remainder.
Since 643,660 cannot be divided by just 1 and 643,660, it is not a prime number.