My IPhone is receiving calls from Israel and Algeria, is it possible it may have been hacked?

I used to use WhatsApp, but I deleted it after they discovered that bug.

Even not WhatsApp users are receiving this calls, just don't answer the phone to any numbers you don't recognize.

The bug is already fixed FYI. Just update to the latest version of the app.

As far as the calls, not sure there. Could change your call settings so it is less open.

Those sort of calls are usually from autodialers

No that doesn't mean you've been hacked. Receiving spam calls is very common, just you've made a connection due to the bad timing of the WhatsApp news (which has been fixed btw)