The kids were discussing fiercely during the school break (ah, those were the times!). The subject: Bragging about who can count up to the highest number.
John said "I can do 20". Jolene said "I know up to 50!". Miles said "I know up to a hundred!".
Little Marie felt sad, she was the youngest and not only had she studied only up to 10, but she was bad at it too. To her great gladness, at that time, her cousin, a science university grad, just strolled up to say hi!
"Big Cousin Nicola, please tell us how high you can count"!
"Well Marie, I'll tell you a more interesting thing instead - I know a number that can itself count"!
What is that number?
The associated knowledge science is not math. Also, no lateral thinking (at least on word level).
The associated knowledge is not programming. Else, any program that implements counting could be interpreted as a number and be the solution.