Friday, 2 December 2011

73 is the magic number

Or rather star number. But I'm getting ahead of myself...

The things is, I've just noticed that this blog now has 73 followers. This is a good thing. For a long time it has had to make do with thirty or so, but recently the number of followers has shot up. (If this is because you* have linked to this blog or promoted it online elsewhere, then thank you. But back to the matter in hand.)

It's interesting that I've noticed this today is because 73 is a special number or, to give it its technical, mathematical name, a star number.

73 is also the 21st prime number. And of course the mirror of 73, is 37 - the 12th prime number. The number 21 has among its factors the number 7 and the number 3.

73 in binary, 1001001, is palindrome. In addition, of the 7 binary digits representing 73, there are 3 ones. Also, 37+12=49 (seven squared) and 73+21=94=47*2, 47+2 also being equal to seven squared.

It is also a sexy prime. No seriously.**

Do you think it's a coincidence that Sandi Tostvig and friends lived at No. 73?

Of course tomorrow this blog could have 74 followers, or more, and the days of star numbers and reversible primes will be but a happy memory...

* Yes, you.

** This should so be over on the Match Wits blog.

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