Q: Is 643,920 a Prime Number?
A: No, 643,920 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 643920 can be evenly divided by 1 2 3 4 5 6 8 10 12 15 16 20 24 30 40 48 60 80 120 240 2,683 5,366 8,049 10,732 13,415 16,098 21,464 26,830 32,196 40,245 42,928 53,660 64,392 80,490 107,320 128,784 160,980 214,640 321,960 and 643,920, with no remainder.
Since 643,920 cannot be divided by just 1 and 643,920, it is not a prime number.