Explanation
601
If the word started with the latter A then the remaining 5 positions can be filled in 5! ways.
Similarly, for the other letters
No. of word starts with A = 5!
No. of word starts with C =5!
No. of word starts with H = 5!
No. of word starts with I = 5!
No. of word starts with N = 5!
Total words = 5! + 5! + 5! + 5! + 5! = 5(5!) = 600
Next when words starting with S appears, SACHIN itself will be the 1st word as ACHIN are all in dictionary order,
Now add the rank of SACHIN.
so rank is 600 + 1 = 601