91.86 percentile in jee mains mean that 91.86 percentage of student are left behind you in competitive exam .A formula is given by National Testing agency to calculate rank.The formula is

No of candidates apperared in exam/100 *(100 - Nta score ).So 869010 candidate appeared in exam .So your rank will be  70737.

But if the no of candidates In April attempt increase to 12 lakh then your rank will vary accordingly.

If you want to predict colleges based upon your rank and percentile then you can visit the link mentioned below.

https://engineering.careers360.com/jee-main-college-predictor

Thanks

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