Q: Is 667,780 a Prime Number?
A: No, 667,780 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 667780 can be evenly divided by 1 2 4 5 10 20 173 193 346 386 692 772 865 965 1,730 1,930 3,460 3,860 33,389 66,778 133,556 166,945 333,890 and 667,780, with no remainder.
Since 667,780 cannot be divided by just 1 and 667,780, it is not a prime number.