Q: Is 678,640 a Prime Number?
A: No, 678,640 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 678640 can be evenly divided by 1 2 4 5 8 10 16 17 20 34 40 68 80 85 136 170 272 340 499 680 998 1,360 1,996 2,495 3,992 4,990 7,984 8,483 9,980 16,966 19,960 33,932 39,920 42,415 67,864 84,830 135,728 169,660 339,320 and 678,640, with no remainder.
Since 678,640 cannot be divided by just 1 and 678,640, it is not a prime number.