I won’t recommend installing antivirus on Android.
Here is why:
1) Applications are sandboxed in Android, this makes Android much more safe than traditional PC systems. Even if you access internet via browser there is a lot less that can happens as compared to PC system.
2) If any app is suspicious then it would get noticed by other people and rated badly in Play Store, in worst cases it would be removed from Play Store by Google, so there is less chance of user installing something malicious by mistake.
3) There would be an always running process after installing anti virus. This affects both performance and battery life.
4) Viruses are the consequences of vulnerability of the system to protect itself from any external programs that work maliciously without the knowledge of user and/or system.
Android Architecture Diagram for understanding android.
Android has built in permission manager nowadays from which you can allow or not allow apps certain permission and most well-known OEMs patch their ROMs with latest patches from Google.
Here’s a preview of permission manager from google’s stock android ROMs.
For instance if you have enabled “USB Debugging” antivirus will scan it as a threat, but you should know that as long as your device is patched by OEM or custom ROM developer you dont need to worry at all.
An antivirus would only create false reports and eat your battery life and may hinder performance.
Conclusion – Android is one of the most secure Mobile Platform OS in my opinion till date.