First YouTube video to require a 64-bit counter

In December 2014, the video to the song "Gangnam Style", by South Korean artist PSY became the first clip on YouTube to garner so many views that the website’s hit counter was unable to keep up. "Gangnam Style" reached a whopping 2,147,483,647 views (2.15 billion) – the biggest number that can be stored using a 32-bit counter (that is, a counter that stores numbers using 32 binary digits). YouTube was able to fix the problem by upgrading the counter to 64 bits. That means PSY is now safe again until "Gangnam Style" reaches 9,223,372,036,854,780,000 – 9.2 billion billion – hits on the video sharing site. Binary numbers are a convenient way for computers to store information because each digit can only take the value 1 or 0 – corresponding to the on-off state of an electronic switch. The biggest number that a 2-bit binary number can store is 1. Each new bit added doubles this limit. So the biggest number that can be stored using 3 binary digits is 2. In general, the biggest number storable by an n-bit binary number is 2 to the power n-1, minus 1. Plug n=32 into this formula and you get the maximum number that could be stored on YouTube’s old 32-bit counter.