We don't usually realize that there are other languages in this world. Spanish community is much more active on the internet than English community when it comes to music. It's also true that these songs are really catchy and stuck in your mind. You can see other Spanish songs having more than billion views. You will be amazed that your never heard about that songs and it has billion views.
Plus it also the hype and of course Justin Bieber. Before Justin the song had around 900million views but after the Justin version came out it just blew up.