What you cannot hold but it is yours?

Find The Next Number in this series.
1, 2, 6, 42, 1806 ?

There are two guys standing face to face in a room. On a wall, there is a clock. One of those is a prophet. He tells the other guy that he will be stabbed in the back in five minutes.

Shocked to hear that, the other guy stares at the clock. Just after the five minutes, he is stabbed on the back. Can you tell what happened?

In a university, a professor gave a set of three problems to the three brilliant students of his class. See the image for the questions.

How many bananas can you eat if your stomach is empty?

There are 2 sand hourglasses.

The small one can measure 5 hours and the large one can measure 7 hours.

How can we measure 16 hours with 2 sand hourglasses running together ?

Replace the question mark with the correct number.

How many sides does a circle have?

There were five men at church, and it started raining while they were outside. The four that ran still got wet, but the one that was still stayed completely dry. Why did he stay dry?

What brings you down but never up?