Microsoft's Spreadsheet app Excel, PowerPoint, OneNote, and OneDrive also have 500 million installs each.
Microsoft Word for Android has been installed more than 1 billion times, according to the Google Play Store.
In addition to Word, the company's other office apps, including Spreadsheet app Excel, PowerPoint, OneNote, and OneDrive, are also performing pretty well with 500 million installs each, whereas Outlook for Android has more than 100 million installs. Android Police points out that it is not necessarily the number of downloads because Microsoft has tie-ups with companies like Samsung, whose phones have Microsoft software and apps preinstalled.
Microsoft Word is a word processor developed by Microsoft and was first released on 25 October, 1983.