Q: Is 642,640 a Prime Number?
A: No, 642,640 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 642640 can be evenly divided by 1 2 4 5 8 10 16 20 29 40 58 80 116 145 232 277 290 464 554 580 1,108 1,160 1,385 2,216 2,320 2,770 4,432 5,540 8,033 11,080 16,066 22,160 32,132 40,165 64,264 80,330 128,528 160,660 321,320 and 642,640, with no remainder.
Since 642,640 cannot be divided by just 1 and 642,640, it is not a prime number.