In my native tongue, Malayalam, there is a question word - "ethraamathe" - which we use to get an ordinal number as answer. In other Indian languages, and also in many foreign languages like Dutch and German, such a question word does exist. But in English there is no one word for such a question.
I have once read in a Phantom strip cartoon book from US a sentence that uses what number. Using this expression it is easy to ask "What number president of America was Abraham Lincoln?" to which one would answer "16th". A professor from Oxford University has said in one of his letters to me that what number can be used in informal speech. In his opinion, "Where in the numerical order did Abraham Lincoln come as President of America?" can be used in writing.
I would like to know whether American and British people use what number in their speech. Some Indians also use how manieth as an ordinal number question.