Q: Is 421,905 a Prime Number?
A: No, 421,905 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 421905 can be evenly divided by 1 3 5 11 15 33 55 165 2,557 7,671 12,785 28,127 38,355 84,381 140,635 and 421,905, with no remainder.
Since 421,905 cannot be divided by just 1 and 421,905, it is not a prime number.