19 (Number)

19 is a number. It doesn't technically exist, but we don't tell it that. Not very many people would feel happy knowing they are non-existant, and numbers work the same.

Origin
One time before time, nobody counted above 15 because they only had one foot. One day, someone was born with two feet!! Therefore, before people got headasploded, the Numberbet council added the numbers 16 through 20 to the Numberbet (excluding 16.5).