I got one too. I think this is what the Whatsapp company. It means that someone somewhere is trying to verify their phone number during signup to Whatsapp, but they've entered their phone number incorrectly. Instead, they have entered yours.
Im really enoyed by this. They keep calling and texting me at night because we're on a different time schedule here in norway. I havent figured out how to make them stop.
11 (eleven!) calls from 04:30 to 07:45, so I have set my mobile to blacklist the number. A friend sent me pics from her iPhone which I couldn't open because I don't have a cross-platform app. Either, she registered my number without my consent (she promises me that she did not) or, my failed attempt to open the images somehow prompted the app. I received a text yesterday containing a code for WhatsApp and a link to tap in order to verify my device. I did nothing. This morning I had the 11 calls, two from 'Minisota' and nine from 'Unknown', but all from the same number and conclude that the calls are to verify that the device is mine. I do not want this app and so will leave my phone to block the number via its blacklist. This facility is provided by the Comodo Mobile Security for Android app which handles unwanted calls brilliantly; this can be reversed if you choose to accept the call in the future.