Q: Is 421,721 a Prime Number?
A: No, 421,721 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 421721 can be evenly divided by 1 53 73 109 3,869 5,777 7,957 and 421,721, with no remainder.
Since 421,721 cannot be divided by just 1 and 421,721, it is not a prime number.