Soupy words

$\text{SESQUIPEDALIANISM, this word can be rephrased as follows according to the question} \\ \text{SSQPDLNSM(EUIEAIAI)} \\ \text{So if you consider all the vowels together as 1 letter, you have 10 words.} \\ \text{So this can be written in 10! ways. } \\ \text{The vowels itself can be written in 8! ways, as there are 8 vowels. Now look at the following} \\ \color{#D61F06}{\text{SS}}\color{#333333}{\text{QPDLN}}\color{#D61F06}{\text{S}}\color{#333333}{\text{M}\text{(}}\color{#3D99F6}{\text{E}}\color{#333333}{\text{U}}\color{#20A900}{\text{I}}\color{#3D99F6}{\text{E}}\color{magenta}{\text{A}}\color{#20A900}{\text{I}}\color{magenta}{\text{A}}\color{#20A900}{\text{I}}\text{)} \\ \text{So, S repeats 3 times, E 2 times, I 3 times, A 2 times} \\ \therefore \text{Total no of ways, }n = \dfrac{10! \times 8!}{\color{#D61F06}{3!} \times \color{#3D99F6}{2!} \times \color{#20A900}{3!} \times \color{magenta}{2!}} \\ \implies n = 1016064000 \\ \boxed{\therefore \text{Sum of digits = } 1+0+1+6+0+6+4+0+0+0 = 18}$