At sea level a barometer having a cross-sectional area of 1 cm2 calculates a pressure of 76 cm of mercury. The pressure exerted by this column of mercury is equal to the pressure exerted by all the air on 1 cm2 of Earth's surface. Given that the average radius of Earth is 6371 km and the density of mercury is 13.6 g/mL, determine the total mass of Earth's atmosphere in kilograms.