Q: Is 643,540 a Prime Number?
A: No, 643,540 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 643540 can be evenly divided by 1 2 4 5 10 20 23 46 92 115 230 460 1,399 2,798 5,596 6,995 13,990 27,980 32,177 64,354 128,708 160,885 321,770 and 643,540, with no remainder.
Since 643,540 cannot be divided by just 1 and 643,540, it is not a prime number.