Well, that can depend on the various factors like size, complexity, and timeframe of the project, multiple developers may be required for the mobile app development process. Typically, a team of 1-3 developers can normally create a small to medium-sized mobile application, however extensive and more complicated apps may need a bigger team.
Depending on the specific requirements of the project, a mobile app development team also consists of designers, testers, project managers, and other profiles.