What makes this number unique: 8,549,176,320?

Two-person want to cross a river. Only one boat is present on the riverside that can carry only one person at a time.

However, they still manage to cross the river. How is it possible?

What is at the end of a rainbow?

Can you convert the number zero(0) into a positive number using just one mathematical operator ?

Can you name an animal whose killing cannot be performed without spilling your own blood?

Be active and find the killer in the picture Riddle below.

Two boys wish to cross a river. The only way to get to the other side is by boat, but that boat can only take one boy at a time. The boat cannot return on its own, there are no ropes or similar tricks, yet both boys manage to cross using the boat.

How?

It's a protector.
It sits on a bridge.
One individual can see directly through it, while others wonder what it hides.

What is it?

Can you replace the X (both small and big x) with the numbers between 1 to 19 such that all the rows of 3 numbers between X (big x) sum to 23?

I am never scared but became petrified and can’t live in a house but would die to make one. What am I?