Q: Is 19,991 a Prime Number?
A: Yes, 19,991 is a prime number.
A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 19991 can be evenly divided by 1 and 19,991, with no remainder.
Since 19,991 can be divided by just 1 and 19,991, it is a prime number.