Q: Is 643,431 a Prime Number?
A: No, 643,431 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 643431 can be evenly divided by 1 3 139 417 1,543 4,629 214,477 and 643,431, with no remainder.
Since 643,431 cannot be divided by just 1 and 643,431, it is not a prime number.