2017 is a central polygonal number: a number of the form k(k + 1)/2 + 1, where k = 63 (A000124). It is the maximum number of pieces of a circular pizza that you can make with 63 straight cuts.
2017, (2017 + 1)/2 = 1009, and (2017 + 2)/3 = 673 are all primes (A036570).
2017 = 502 + 504 + 505 + 506 (the sum of four consecutive composite numbers) (A060329). 2017 is also the sum of eight consecutive composite numbers (A060333).
Welcome to an occasional series devoted to "cool stuff" that I encounter while browsing the world of mathematics and computer science. I'll peek at new developments in math and its applications, and I'll revisit old puzzles, famous problems, and historic events—anything mathematical that happens to catch my eye. I hope you'll find something of value in these brief, informal forays into the world of math.
Ivars Peterson is a freelance writer and editor. He was Director of Publications at the Mathematical Association of America from 2007 to 2014. As an award-winning mathematics writer, he previously worked at Science News for more than 25 years and served as editor of Science News Online and Science News for Kids. His books include The Mathematical Tourist, Islands of Truth, Newton's Clock, and Fragments of Infinity: A Kaleidoscope of Math and Art.