Q: Is 421,857 a Prime Number?
A: No, 421,857 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 421857 can be evenly divided by 1 3 9 19 57 171 2,467 7,401 22,203 46,873 140,619 and 421,857, with no remainder.
Since 421,857 cannot be divided by just 1 and 421,857, it is not a prime number.