Phosphorus has an atomic number of 15 and a mass number of 3…

Phosphorus has an atomic number of 15 and a mass number of 31. Hydrogen has an atomic and mass number of 1. Oxygen has an atomic number of 8 and a mass number of 16. Sodium has an atomic number of 11 and a mass number of 23. What is the molecular weight  (Na2HPO4)?