I have deactivated my Viber account about 8 month ago. However my account still appears on my friend lists as follows:
This contact was online 03/16/2014"
How to disappear completely from my friend lists?
You will need to follow the online procedure in order to deactivate your account. There is also the possibility that your friends didn't update the contact list for a very long time. Ask them to go to Contacts > Contacts Refresh. This should get you off their list.