Q: Is 643,960 a Prime Number?
A: No, 643,960 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 643960 can be evenly divided by 1 2 4 5 8 10 17 20 34 40 68 85 136 170 340 680 947 1,894 3,788 4,735 7,576 9,470 16,099 18,940 32,198 37,880 64,396 80,495 128,792 160,990 321,980 and 643,960, with no remainder.
Since 643,960 cannot be divided by just 1 and 643,960, it is not a prime number.