Customizable Financial Calculator App with Google Drive Integration

I'm looking for an Android and iOS calculator app that not only performs financial calculations but also allows users to customize its interface with themes. A standout feature of this app is a button that saves user-selected calculations to their Google Drive file.

Key Requirements:
- Customizable interface with themes
- Capable of performing financial calculations
- Save user-selected calculations to MS SQL Server
- Simple, intuitive, and engaging design
- Financial Report - Daily, Monthly, Yearly
- Application should be comparable with any device

Ideal Skills:
- Expertise in mobile app development, particularly Android and iOS
- Experience in designing customizable user interfaces
- Competence in implementing MS SQL Server
- Proficiency in creating financial calculator apps
- Ability to deliver a simple and intuitive design