why number 8549176320 is one of a kind?

You have to put a letter on the following to make it a meaningful word. The only challenge is that you can't use 'E'.

S E Q U E N C _

I know a nine-letter word having only one vowel.
Do you ?

Replace the question mark with the correct number, given the pair of numbers exhibits a similar relationship?

? : 3839 :: 11 : 1209

There are nine letters in the below-given diagram. You have to form a nine-letter word using these letters.

There are three houses in a straight row. One is red, one is blue, and one is white. The red house is left of the middle. The blue house is right of the middle. Where's the white house?

What comes
Once in a Year
Twice in a Month
4 times in a Week
6 times in a Day

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

Nine marbles are arranged in the image below. Can you slide two marbles to form a square?

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