# Take any prime number, say, 27...February 14, 2010 8:03 PM   Subscribe

Whose prime is 27? I remember that 27 is called So-And-So's Prime because he said in a lecture, "take any prime, say, twenty-seven..." but I can't remember who said this (and googling only gives me pages about how 27 isn't a prime number).
posted by joannemerriam to Science & Nature (9 answers total) 5 users marked this as a favorite

You might be thinking of 57, the "Grothendieck prime".

See the end of the first page of this article about Alexandre Grothendieck from the Notices of the American Mathematical Society.
posted by madcaptenor at 8:08 PM on February 14, 2010

27 is not prime. 3 x 9 == 27.
posted by smcameron at 8:20 PM on February 14, 2010

27 is not prime. 3 x 7 == 27.

I think that's the point. It's a verbal mistake someone made.
posted by drjimmy11 at 8:22 PM on February 14, 2010

The point is that some mathematicians, despite studying prime numbers, don't actually know which numbers are prime. If I'm right in attributing this to Grothendieck, it's worth pointing out that Grothendieck is well-known as a proponent of a very abstract approach to mathematics. More than that I won't say, despite being a mathematician, because I don't think I can competently explain it.
posted by madcaptenor at 8:28 PM on February 14, 2010

I'm not having that little o! of recognition for the name Grothendieck but that doesn't mean he's not the guy I'm thinking of. His prime being 57 works nearly as well for my purposes, which is to make a joke for a mathematician friend.
posted by joannemerriam at 8:42 PM on February 14, 2010

One striking characteristic of Grothendieck’s mode of thinking is that it seemed to rely so little on examples. This can be seen in the legend of the so-called “Grothendieck prime”.
In a mathematical conversation, someone suggested to Grothendieck that they should consider a particular prime number. “You mean an actual number?” Grothendieck asked. The other person replied, yes, an actual prime number. Grothendieck suggested, “All right,take 57.”
--From a blog.
posted by exphysicist345 at 10:15 PM on February 14, 2010

127 is a mersenne prime.
posted by be11e at 6:44 AM on February 15, 2010