Hi Guys, I have Android Tablet. The version it has is 6.0.1.I am new to it. I want to know the best free software for the following. 1. Anti-Virus (with Firewall) 2. PDF Reader (with faster search results for Particular words). 3. Eraser (for secure erasing) 4. Free Space Cleaner 5. App Lock 6. Folder Lock You may recommend any other apps which you have found useful.