what is 911 ?

It is a number which is less than 1000 and more than 0. It is also a prime number that means it can not be divide by any others number:). can my answer acceptable?

In the USA it is the number you dial for emergancy response and also the date of the terrosit attacks, the day the planes were highjacked and 2 were crashed into the Twin towers of the World Trade Center in New York, one into the pentagon in Washington DC and one was crashed into the ground in Pennsylvania. Thousands of lives were lost and millions of families were hurt. It is a very sad day in the history of America if not the whole world.