more prop blades mean greater engine/aerodynamic efficiency
Quite the reverse. The fewer the number of prop blades the greater the efficiency. The highest theoretical efficiency would be gained with a one bladed prop, but of course a great number of engineering considerations come into play to determine what trade offs will be made to come up with an optimum overall package that represents the final aircraft. The C-130 started life with 3,750 HP and three bladed props, then 4,050 HP and four blade props and finally 4,591 HP and six blade props. In each case it was necessary to increase the solidity by adding blades to absorb the increased power, not to increase efficiency, which in fact would be decreased. Prop diameter was of course limited by the fuselage/engine/engine spacing.