Given:
The word is ATONEMENT.
The number of letters in this word are 9 and unique letters are 6.
Arrangement of the letter is calculated as,
[tex]\begin{gathered} n\text{ letters are arranged in n! ways} \\ Arrangement=9!\text{ } \end{gathered}[/tex]But as the 3 letters are repeated 2 times.
So, the number of unique arrangements are,
[tex]\text{Arrangement}=\frac{9!}{2!2!2!}=\frac{362880}{8}=45360[/tex]Answer: Number of arrangements are 45360.