What's Special About This Number? | Hacker News Reader

What's Special About This Number?

stetson.edu

11 pointsmarkup12 comments

2 is the only even prime?

Objection! This amounts to "2 is the only prime not divisible by 2"! How about 2 is the highest solution for N in any equation X^N + Y^N = Z^N?

3 is the number of spatial dimensions we live in?

Objection! This is a mere contingent empirical fact! This is a fact about our universe, not the number 3! You might as well say that your car has three seats in the back. How about "3 is the first number whose factorial does not equal itself"?

3 dimensions is the smallest number of dimensions in which you can make a practical universe. For example photons could not exist in a 2 dimensional universe.

I do get your point that it's not a mathematical property of the number. (But I think you can find some geometrical something that only works in 3 dimensions.)

Dont go there if you have the slightest interest in numbers. Your day will evaporate before your eyes. :-)

"9951 is the number of ways to color the vertices of a triangle with 31 colors, up to rotation."

Thank you! I was wondering about that just last night over beer. Now I can sleep easy :-)

Seriously the only thing missing:

1 is the number of web site authors with way too much time on their hands.

1 is the number of web site authors in evidence with way too much time on their hands.

"88 is the only number known whose square has no isolated digits"

Anyone that can explain this?

http://en.wikipedia.org/wiki/7744_(number)

Which also says "There are also very few squares with no unpaired digits", so the 'only number' bit seems erroneous (it did sound hard to believe).

I feel sorry for 356, the smallest number about which there is nothing "special". But perhaps that is itself special! Repeat.

I guess that means that it is the smallest gojomo number. I think 40 is a little forced (only number whose name is spelled in alphabetical order). You should claim 40 too.

Agreed about 40. That answer only works in English.

"69 has the property that n2 and n3 together contain each digit once."

Indeed.

The 897x's are cheating.

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