The total no. of letters in the word ASSASSINATION = 13, in which there are 3A’s, 4S’s, 2N’s and 2I’s. When all S’s are taken together then take it as one object. Thus, we have a total of (9 + 1) letters. ∴ Required no. of words = $\frac{10!}{36!\,2!\,2!}$ = $\frac{10 \times 9 \times 8 \times 7 \times 6 \times 5 \times 4}{2 \times 2}$ = 151200