Microsoft Office is really excelling in the PlayStore as one or part of the Office Apps Excel hits 1 billion installs with over 2 million reviews.
Microsoft Excel is a spreadsheet developed by Microsoft for Windows, macOS, Android and iOS. It features calculation, graphing tools, pivot tables, and a macro programming language called Visual Basic for Applications.
The 1 billion mark is only in the Google PlayStore and not counting the Apple App Store and Microsoft Store.
Microsoft has a bunch of apps but the Office Apps make a case of decency. I learned right with Outlook for Android been pretty damn good email client both for my corporate and private use.
Installation of Outlook is extremely easy with Autodiscovery and Excel works fine strongly competing in preference with Gsuite Google Sheets.
Microsoft Word for Android already has a 1B+ installations while Outlook lingers in the 100M+ but Microsoft PowerPoint is beyond 500M+ installs.