What is the next number in this series?

4,12,84,3612....

Can you solve the below algebraic mathematical equation?

(J+O+I+N+T)3 = JOINT

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

What country can make you shiver?

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?

I have a head like a cat and feet like a cat, but I am not a cat. What am I?

Who always enjoys poor health?

When does a USA Potato change its nationality?

I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?

Find out which of the given views in the picture is accurately the top view of the given pyramid.