Viber Stats and Facts
With Viber, everyone in the world can connect. Freely. Viber users can send free text messages, photo messages, video messages and share locations with other users. Users can also make free HD-quality calls to other Viber users on iPhone®, Android™, Windows Phone, Blackberry®, Windows®, Mac, Symbian, Nokia S40 and Bada devices over 3G/4G or WiFi connections. (source)
Please note that some of these numbers are easier to find than others. A few of these stats come from the company’s own reports, but some are based on news reports and not official company tallies. Basically, this is the best I can find and I don’t guarantee anything to be 100% accurate.