Q: Is 391,821 a Prime Number?
A: No, 391,821 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 391821 can be evenly divided by 1 3 131 393 997 2,991 130,607 and 391,821, with no remainder.
Since 391,821 cannot be divided by just 1 and 391,821, it is not a prime number.