Admission to BS courses at IIT is offered on the basis of JEE Advance and not JEE Main at this percentile you will surely qualify for jee advance.

You can calculate your rank by the following formula

(100-Percentile score)*869010/100, Therefore your rank is 37628

If the number of student get increased to 1200000 then the rank would be

(100-Percentile rank)*1200000/100 ,which is 51960

Meanwhile ,You can use JEE Main college predictor to predict the possible college which you may get the link is given below.