Q: Is 16,821 a Prime Number?
A: No, 16,821 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 16821 can be evenly divided by 1 3 7 9 21 27 63 89 189 267 623 801 1,869 2,403 5,607 and 16,821, with no remainder.
Since 16,821 cannot be divided by just 1 and 16,821, it is not a prime number.