Q: Is 31,780 a Prime Number?
A: No, 31,780 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 31780 can be evenly divided by 1 2 4 5 7 10 14 20 28 35 70 140 227 454 908 1,135 1,589 2,270 3,178 4,540 6,356 7,945 15,890 and 31,780, with no remainder.
Since 31,780 cannot be divided by just 1 and 31,780, it is not a prime number.