Bharat, you can calculate your expected JEE Mains rank using the following formula:

(100-your total percentile) x 869010/100

So with 84.58 percentile, your rank would be around 134001.

Also, if the number of students increases to 12 lakh in the April session, the formula for rank calculation would change to:

(100-your total percentile) x 1200000/100

Hence your expected rank in this case would be around 185040.

While it is difficult to predict the exact qualifying cutoff, a percentile of 85 or above is decent enough to qualify for JEE Advanced. In 2019, the NTA score cutoff for the Common Rank List was 89.7548849

According to your percentile, it might be difficult to clear the cutoffs for JEE Advanced. Also you might not be able to get a seat in the top NITs or IIITs with this rank. I would suggest you to sit for the April session as you are only lagging behind by a little. Give your best in the next session so that your chance of qualifying JEE Mains and getting a top college increases. Solve the previous years' papers, brush up your concepts and revise thoroughly.

You can also go through our college predictor to check which colleges you are eligible for through your JEE Mains score. The link for the college predictor is:

All the best.