$\textbf{Unique Number}$
What makes the number $8549176320$ unique?
$\textbf{Answer}$
This is the only number which contains all the digits sorted by the alphabetical order of their English spellings, i.e. Eight, Five, etc.
$\textbf{Note}$
This cannot be a pure math problem because processing such a large number usually requires a calculator or a computer. These tools are not provided in solving a brain teaser.