According to a post on YouTube's Google+ page, Japanese singer Psy's 'Gangnam Style' beat their assumption of the maximum number of views a video posted on their platform can have.

The video which was uploaded in July 2012 has raked in more that 2.1 billion views, which is so large they had to upgrade their system so more views are accounted for. Read the official statement...

"We never thought a video would be watched in numbers greater than a 32-bit integer (=2,147,483,647 views), but that was before we met PSY. "Gangnam Style" has been viewed so many times we have to upgrade!

Hover over the counter in PSY's video to see a little math magic and stay tuned for bigger and bigger numbers on YouTube."

Source: http://www./forum/entertainment/celebrities/6856-psys-gangnam-style-forces-youtube