How many doors are there in Boeing 747?

Answer 1

10 Passenger entry doors, 2 emergency passenger escape doors on the upper deck, 4 escape doors over the wings, 1 small escape door in the cockpit ceiling, 2 main cargo doors, 1 smaller bulk cargo door, 2 electrical compartment doors under the fuselage (1 of which provides access to the passenger compartment), and at least 7 other maintenance access doors in the wings, fuselage, and empennage (tail).

To answer, that's 22 external doors not counting maintenance accesses, 20 which can get you into the pax compartment (rear and bulk cargo compartments have no access).

This also doesn't count landing gear doors of which I believe there are 6) and internal doors as this will vary with the # of toilets and closets and crew rest comartments installed.