Q: Is 421,638 a Prime Number?
A: No, 421,638 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 421638 can be evenly divided by 1 2 3 6 7 14 21 42 10,039 20,078 30,117 60,234 70,273 140,546 210,819 and 421,638, with no remainder.
Since 421,638 cannot be divided by just 1 and 421,638, it is not a prime number.