There are 8 billion people most of whom know little or nothing about the world outside of their region or nation. We are among the educated elite and that is the group such discussions have some playful meaning. I'd be surprised if a billion people know anything about ancient Greece or could name a picture of the Parthenon. The World Cup is likely much better known among masses. What was Pele's number?
All I know about Pele is that way back when, he was an often-used solution to a crossword puzzle clue.
As for ancient Greece, the daft curriculum that is in the process of being foisted on the students of my province included an assignment for Grade 2 kids - who are SEVEN YEARS OLD - to draw a map of ancient Greece and label the Greek cities and the nearby bodies of water.
Even I can't remember how to spell some of that half the time, and I took Roman and Greek history in college!
Does that really count as a number, though? It has units, so in different unit systems it has a different numerical value.
In my opinion, a constant should be dimensionless to really be a number. Like the Avogadro number.
I kid you not, the first time one of my teachers uttered the phrase "Avogadro number", I heard it as "avocado number". And I've never even tried an avocado.
If you want famous units, though, any Original Trilogy Star Wars fan knows that the Millennium Falcon made the Kessel Run in 12 parsecs - even if most of them snicker at George Lucas' ignorance of types of measurements used in astronomy.
Everyone knows (or should) 1492, yup.
It's got a lot of negative associations nowadays, though. And every time someone trots that date out to me as "evidence" of some kind of superior feat of European exploration, I just inform them that the Vikings got here first - 500 years earlier.
That said, I love the soundtrack Vangelis composed for the movie. It's possible to love the music but loathe the main character.