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Goodbye to 2017, a Prime, Sexy, Odious Year

BloombergOpinion

(Bloomberg View) -- The year 2017 has had its ups and downs. Mathematically, however, one thing is certain: The entire year has been prime time.

For a math geek like me, the properties of numbers are a source of excitement and fun. In that spirit, it’s a joy to point out that 2,017 is a prime number — that is, an integer only divisible by 1 and by itself.

And it’s not just any prime. It’s half of what mathematicians call a “sexy prime pair.” Before you get any abnormal impressions of mathematicians, I should clarify: Here, “sexy” comes from “sexa,” the Latin root for “six.” The term means that 2,017 is separated from another prime, in this case 2,011, by exactly 6.

That’s not all. If we multiply 2,017 by pi — the ancient constant that equals the circumference of a circle divided by its diameter — and then round to the nearest integer, we get another prime number: 6,337. We also get a prime if we start with 2,017 and tack on every decimal digit at the end to get 20,170,123,456,789.

It’s possible to cut a pizza into 2,017 slices using only 63 straight cuts across the whole pie. And if we convert 2,017 to its binary equivalent made up only of zeros and ones — 11111100001 — it becomes what mathematicians call odious.

So what should we expect from 2018? Next year isn't a prime number, but it’s about as close as you can get: 2,018 only has two factors — it’s 2 times 1,009. That makes it semiprime, not to be confused with subprime (a type of loan). And 2,018 is also a prime-part-partition number, but that’s a story for next December.

In the meantime, I hope you enjoyed your prime time while you had it. The next prime year after 2017 is 2027, a decade away. Hmm, now add 2 + 0 + 1 + 7 to 2,017 and see what you get.

Happy New Year x 10!

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.

Scott Duke Kominers is the MBA Class of 1960 Associate Professor of Business Administration at Harvard Business School, and a faculty affiliate of the Harvard Department of Economics. Previously, he was a junior fellow at the Harvard Society of Fellows and the inaugural research scholar at the Becker Friedman Institute for Research in Economics at the University of Chicago.

  1. I’m not the only one who thinks this way check out  this post  by  TJ Wei  from earlier this year, and this one  from the  Mathematical Association of America which for some reason was posted in

  2. And indeed,

  3. That’s not mathematical social commentary it just means that the binary expansion has an odd number of ones.

To contact the author of this story: Scott Duke Kominers at kominers@fas.harvard.edu.

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