1 m^2/µg (Meter^2/Microgram) is equal to 999,999,999,999.9999 mm^2/g (Millimeter^2/Gram). To convert from Meter^2/Microgram to Millimeter^2/Gram, multiply by 1,000,000,000,000 or divide by 0.000000000001.
Nine Hundred Ninety-Nine Billion Nine Hundred Ninety-Nine Million Nine Hundred Ninety-Nine Thousand Nine Hundred Ninety-Nine Point Nine Nine Nine Nine Millimeter^2/Gram