What is the density of Mercury with respect to air?

The density of Mercury is 13,593 kg/m3, whereas the density of air (at sea level and 20 degress C) is about 1.2 kg/m3. Hence, Mercury is about 11,328 times denser than air. (Divide 13,593 by 1.2.) Note that the density of air varies greatly with temperature and pressure.