Q: Is 643,995 a Prime Number?
A: No, 643,995 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 643995 can be evenly divided by 1 3 5 9 11 15 33 45 55 99 165 495 1,301 3,903 6,505 11,709 14,311 19,515 42,933 58,545 71,555 128,799 214,665 and 643,995, with no remainder.
Since 643,995 cannot be divided by just 1 and 643,995, it is not a prime number.