Q: Is 561,666 a Prime Number?
A: No, 561,666 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 561666 can be evenly divided by 1 2 3 6 7 14 21 42 43 86 129 258 301 311 602 622 903 933 1,806 1,866 2,177 4,354 6,531 13,062 13,373 26,746 40,119 80,238 93,611 187,222 280,833 and 561,666, with no remainder.
Since 561,666 cannot be divided by just 1 and 561,666, it is not a prime number.