internal storage - Can a app store data beyond uninstallation?

I've an app that creates an account for me but uses no login credentials (starting the app logs me into the account).

• When I uninstall and reinstall the app it still logs mit into my account.



• When I reset my Android Phone (e.g. new OS) it does not remember my account

My question is: What possibilities could this app have to do such behaviour and how do I eradicate it completely from my phone when uninstalling it?