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

What is wrong in the below Picture?

He digs out tiny caves and stores gold and silver in them. He also built bridges of silver and made crowns of gold. They are the smallest you could imagine. Sooner or later everybody needs his help, yet many people are afraid to let him help them. Who is he?

I speak without a mouth, and hear without ears. I have no-body, but I come alive with the wind. What am I?

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

John killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

What number do you get when you multiply all of the numbers on a telephone's number pad?

Why is 6 afraid of 7?

Nodes are shown below and you need to connect them based on the following rule: Every node can be connected to the number of nodes inside them, i.e. the first node there is a value of 1 which indicates that the first node can connect to exactly one node only.Can you do it?

Can you name any English verb that becomes its past tense by simply rearranging the alphabets ?