You can block a number with many apps in the Google Play Store like Mr Number, WhitePages ID, Phone Warrior, TrueCaller etc....most ID the caller and all will allow you to block unlimited numbers for free.
On your note 3 you can auto reject numbers in one of two ways. (from the device)
1) settings / call / call reject
2) go to your call log / long hold on the number you want blocked / add to reject list or block the number