Can you fill the blank with the correct number?

6 30 870 756030 _____

I’m tall when I’m young, and I’m short when I’m old. What am I?

Vin Diesel is pulling a theft and has planned to run away with all the cash kept in the safe. But the only way to open the safe is the 13 character password. He has a set of five clues given to him by a trustworthy source.

Exactly two of the below statements are false.
The password is contained within this sentence.
The password is not in this hint.
The password is within only one of these statements.
At least one of the above statements is a lie.

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

You can see it everyday, But cannot touch it at will. What is it?

Forwards I am heavy, backward I am not. What am I?

What is in seasons, seconds, centuries and minutes but not in decades, years or days?

My cousin lives in one story house in Antarctica. His house is made the of-of sandstone. what is the color of stairs?

If you go to the movies and you're paying, is it cheaper to take one friend to the movies twice, or two friends to the movies at the same time?

Which part of London exists in France as well ?