What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see? What is it?

Replace the question mark with the number below given a simple math problem.

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

Can you find any error in the following sentence?

A taxi was standing outside a fort at night. A man came out of the fort, opened the gate and hit the taxi driver killing him instantly. He took all the money out of the meter and started running till he was caught by a local sheriff.

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

A man who was outside in the rain without an umbrella or hat didn’t get a single hair on his head wet. Why?

While house hunting in London, I came across a very good leasehold property Discussing the lease the landlady told me:

'The property was originally on a 99 years lease and two-thirds of the time passed is equal to four-fifths of the time to come. Now work it out for yourself and see how many years are to go!

Before Mount Everest was discovered, what was the highest mountain in the world?

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?

Can you count the number of seconds in a year?

Clue: You need to bother about calculation.