Q: Is 642 a Prime Number?
A: No, 642 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 642 can be evenly divided by 1 2 3 6 107 214 321 and 642, with no remainder.
Since 642 cannot be divided by just 1 and 642, it is not a prime number.