Q: Is 21,931 a Prime Number?
A: No, 21,931 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 21931 can be evenly divided by 1 7 13 91 241 1,687 3,133 and 21,931, with no remainder.
Since 21,931 cannot be divided by just 1 and 21,931, it is not a prime number.