5000000000 (number)

5000000000 was a number.

The Ninth Doctor approximated the year 5.5/Apple/26, also known as "the year five billion", as five billion years in the future from Rose Tyler's native time of 2005. (TV: The End of the World, New Earth)

According to the Ninth Doctor, the population of Earth in the year 2006 was five billion. (TV: World War Three)