The Harry Potter is ostensibly one of the greatest literary works in the modern century. By J.K.Rowling, the wizarding tales of Harry Potter are littered with easter eggs.
The number 13 is apparently unlucky, according to Trelawney, as whomever the first person to rise from a table containing that number of people will be the first to die. This prediction is proven accurate with the deaths of Sirius and Lupin. both men departing a table of 13 first.
The code used when Harry and Mr. Weasley arrive at the Ministry of Magic is 62442. When used on a phone, it spells out MAGIC.