Q: Is 21,666 a Prime Number?
A: No, 21,666 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 21666 can be evenly divided by 1 2 3 6 23 46 69 138 157 314 471 942 3,611 7,222 10,833 and 21,666, with no remainder.
Since 21,666 cannot be divided by just 1 and 21,666, it is not a prime number.