The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

If an earthquake is 1 point higher on the Richter Scale than another earthquake which is actually 10 times stronger, how much stronger would an earthquake be if it was just half a point higher on the Richter scale?

What number comes next in this sequence:
7 8 5 5 3 4 4 _

Who always enjoys poor health?

When you say goodbye, I am what you need to tie.
I come as a couple and go wherever you run.
Who am I?

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.

Consider this about a word: The first two letters signify a male, the first three letters signify a female, the first four letters signify a great, while the entire world signifies a great woman. What is the word?

Bopanna was working on a murder case when he received a message about the location of the murder weapon.
The message was encrypted as below.

"deb mitciv eht edisni neddih si nopaew redrum ehT"

Tell me the location of the murder weapon.

What number divided by 4 is the same as that number minus 4?

Can you make a six-letter word using the letters N, A and B ?