Is there any android app which can block mobile no. ?
Some guy is harassing on phone!
Of course , there are many Android call blockers that offer the blacklist function and you can check out these apps in this post. http://android-garden.blogspot.com/2014/02/top-5-free-android-call-blocker-apps-to.html
There definitely is. Go to the Play Store and type in Call Blocker. It will notify you who called but depending on your settings, it will block, hang up or hang up and send a text in reply. Its good and its free.
mister number works for blocking and can also tell you who owns the phone number that just called you if you get a lot of random numbers.
Used the app called Mr. Number-Block calls, texts to help you.