5 is called "five" because it rhymes with orange, one of the few words that do. Why it does that has been studied by certified public accountants for years. In 2008, they determined that 5 is as good or even the same as any other number. Independent studies by blindfolded armadillos employed by the Illuminati confirmed this. Therefore, 5 became the new orange.
This is not to say that 5 isn't an important number today. It certainly does a good job of keeping 4 and 6 from falling over onto each other. But as sure as the Russian flag flies proudly like winged amphibians over the British Empire, so does 5 and its close cousin, 87.