First you know there is 12 letters
onomatopoeia
oooonmaatpei (organised)
There is more of one letter. 4 O's. 2 A's.
So
$${\frac{{\mathtt{12}}{!}}{\left({\mathtt{4}}{!}{\mathtt{\,\times\,}}{\mathtt{2}}{!}\right)}} = {\mathtt{9\,979\,200}}$$
This is the answer.