Your question means reverse geo coding - coordinates > geo object (building or plot) > Makani Number. Its algorithm work based Makani Addressing System (in Dubai).

All buildings and plots in the Emirate of Dubai registered in Dubai Land Department.

I read that geo analytical agency Smart Indexes at this summer created Makani Search API - with geo coding: direct and reverse to completing tasks of search by address, building title, Makani Number or Parcel ID. Check it, maybe Makani Search API is available now.