why number 8549176320 is one of a kind?

Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

Can you find the next number in the below sequence
3 , 7 , 10 , 11 , 12 , 17 ?

I know a ten-letter word in the English language which can be typed using only the top rows of the computer keyboard.

A farmer went to a market and bought a wolf, a goat, and a cabbage. On his way home, the farmer came to the bank of a river and rented a boat. But crossing the river by boat, the farmer could carry only himself and a single one of his purchases: the wolf, the goat, or the cabbage. If left unattended together, the wolf would eat the goat, or the goat would eat the cabbage. The farmer’s challenge was to carry himself and his purchases to the far bank of the river, leaving each purchase intact. How did he do it?

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

In the picture, you can see a chess board. On the top left position, the K marks a knight. Now, can you move the knight in a manner that after 63 moves, the knight has been placed at all the squares exactly once excluding the starting square?

There was a blind man. He had four socks in his drawer either black or white. He opened it and took out two socks. Now the probability that it was a pair of white socks is 1/2.

Can you find out the probability that he had taken out a pair of black socks ?

Teacher ask the student

'Why are you standing on that chair in music class ?'.

what did student replied ?

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?