Q: Is 642,621 a Prime Number?
A: No, 642,621 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 642621 can be evenly divided by 1 3 7 21 71 213 431 497 1,293 1,491 3,017 9,051 30,601 91,803 214,207 and 642,621, with no remainder.
Since 642,621 cannot be divided by just 1 and 642,621, it is not a prime number.