If you are using Microsoft Intune as client and/or device management solution, you have to be aware that Microsoft will make the Azure Authenticator app a requirements for Android devices in September 2015.
You can opt out this requirements using the Intune management portal through the Mobile Device Management\Android
If you opt out you need to know that later this year (when the Company Portal app will be updated), single sign on for Intune and Office Apps will no longer be supported and conditional access users will be quarantined on Android devices.
To know more about the Azure Authenticator app, go to http://aka.ms/sept2015