Office in your pocket (but not on your tablet).
Apple's iOS finally got Microsoft's Office 365 at the end of June and now, a little over one month on, Microsoft is looking after Android users. The company today released Office 365 for Android. Similar to the launch of Office 365 for iOS, this one is for Office 365 subscribers only, which means you'll have to get a subscription to Microsoft's Office 365 Home Premium and ProPlus before you can use the app.
Interestingly, Microsoft has made it abundantly clear that this is Office for Android phones as opposed to Android devices (i.e., phones and tablets). Despite the fact that Microsoft's productivity apps would arguably be more useful for those with tablets, Office 365 for Android is explicitly for smartphone users (similar to how Office 365 for iOS doesn't have a dedicated tablet interface).
If you don't have an Office 365 subscription and don't fancy forking over the cash just to try the app, you can get a 30-day trial on office.com.