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

What is black when you buy it, red when you use it, and gray when you throw it away?

Find the 8 in the below-given Image.

You stand in front of two doors. A guard stands next to each door. You know the following things: one path leads to paradise, the other leads to death. You cannot distinguish between the two doors. You also know that one of the two guards always tells the truth and the other always lies. You have permission to ask one guard one question to discover which door leads to paradise. What one question would you ask to guarantee you enter the door to paradise?

I have no life, but I can die. What am I?

What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

I noticed one of the words in the oxford dictionary is spelled incorrectly. What about you?

How do you go from 98 to 720 using just one letter?

A man is found hanging dead from the ceiling of a room. The room’s dimensions are 15 x 15 x 15. The man is only 6ft tall and the rope was only 2ft long. There are no windows and only one door to the room. The door is bolted shut from the inside, and a puddle of water is under the man. How did he kill himself?

Outside a tattoo artist's shop, there was a signboard which read 'I make tattoos on only them who do not tattoo themselves'.

Reading it what do you think, does the tattoo artist tattoo himself?