Q: Is 640,635 a Prime Number?
A: No, 640,635 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 640635 can be evenly divided by 1 3 5 15 42,709 128,127 213,545 and 640,635, with no remainder.
Since 640,635 cannot be divided by just 1 and 640,635, it is not a prime number.