Which equivalence factor should you use to convert from 4.28 x 1019 molecules of oxygen (o2) to moles of o2?

The equivalence factor I should use should involve the Avogadro Number which is 6.02 * 10²³.

6.02 * 10²³ molecules of Oxygen are present in 1 mole of Oxygen molecule.

4.28 * 10¹⁹ molecules of Oxygen would be:

                                                                       = 4.28 * 10¹⁹ * 1 /(6.02 * 10²³)

                                                                       ≈ 0.0000711  moles

So 4.28 * 10¹⁹ molecules of Oxygen is  ≈ 0.0000711  moles

The water cycle increase the water content in the earth atmosphere