Q: Is 645,571 a Prime Number?
A: Yes, 645,571 is a prime number.
A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 645571 can be evenly divided by 1 and 645,571, with no remainder.
Since 645,571 can be divided by just 1 and 645,571, it is a prime number.