So tomorrow the world is supposed to end. Okay, not quite. The rapture will begin. Apparently Earth won’t be destroyed until October 21. So you have some time to get your $@*% together.
There are 21 dots in this star
But this isn’t the only reason that the number 21 is significant. Here are some other interesting (in a pocket-protector kind of way) facts about this Very Important Number.
- 21 is the sum of the dots on a die: 1 + 2 + 3 + 4 + 5 + 6 = 21
- 21 is a Fibonacci number: 1, 1, 2, 3, 5, 8, 13, 21, …
- 21 is the third “star number.”
- 21 is smallest number of differently sized squares that are needed to tile a square.
- 21 is the legal drinking age in the U.S. (Not so math geeky, eh?)
- Blackjack baby!
- [pmath]{2^21}-21[/pmath] is a prime number.
Anything you want to add? Or are you too busy packing your bags?
What is a “star number” ?
Good question, Not Evelyn!
Take a look at the picture in the post — doesn’t it look a little like a star? Now, count the dots in that picture. You should get 21. So when you can take a certain number of dots and arrange them into a star-like figure, that number is a star number.
(Full disclosure here: some purists consider star numbers as only those that form stars that look like a Chinese checkers board. I figure there’s lots of room in the world for different kinds of stars, right?)