Q: Is 666,999 a Prime Number?
A: No, 666,999 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 666999 can be evenly divided by 1 3 9 37 111 333 2,003 6,009 18,027 74,111 222,333 and 666,999, with no remainder.
Since 666,999 cannot be divided by just 1 and 666,999, it is not a prime number.