Find the next number in the sequence

1, 2, 6, 21, 88, __?

You enter your friend's room. He is not in his room. Although you see that on the bed there are two dogs, five cats, two giraffes and three pigs. Also, a couple of chickens and ducks are flying in the room.

Calculate the number of legs standing on the floor.

What is always in front of you but can’t be seen?

How can you leave a room with two legs and return with six legs?

How many people must be gathered together in a room, before you can be certain that there is a greater than 50/50 chance that at least two of them have the same birthday?

The following "Brain Bat" means Slow Down.
S
L
O
W

Using the same logic, can you tell us what does the following Brain Bat means ?
E
V
I
G

P is the father of Q and S is the son of R. T is the brother of P and has a daughter U. If R is the sister of P, then what is the relation between U, Q and S?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

What does the below rebus puzzle mean?

Count the Triangle in the figure given below: