why number 8549176320 is one of a kind?

What does this rebus means ?

There are three light switches outside a room. One of the switches is connected to a light bulb inside the room.
Each of the three switches can be either 'ON' or 'OFF'.

You are allowed to set each switch the way you want it and then enter the room(note: you can enter the room only once)

Your task is to then determine which switch controls the bulb?

A new Engineering building containing 100 offices had just been completed. John was hired to paint the numbers 1 to 100 on the doors. How many times will John have to paint the number nine (9)?

How many words can a pen with half refill write?

How many points are there on the globe where, by walking one mile south, then one mile east and then one mile north, you would reach the place where you started?

You need to arrange three 7 and mathematical symbols to form number 1?

John is pretty weird. He likes toffees but hates chocolates. He loves books but never reads. He likes to build his troops in an online game but does not proceed with the war. He likes to go swimming but is afraid of water.

Seeking this behaviour, can you tell whether he likes balloons and parties?

Can you count the number of triangles in the given picture?

What part of Turkey has the most feathers?