The Cattle of the Sun: a 2,000-year-old poem hides a monstrous number
A Greek epigram attributed to Archimedes describes the Sun god's cattle grazing on Sicily in four colors — white, black, yellow, and dappled bulls and cows — and lays out a set of ratios between them, plus two extra conditions: the white and black bulls together must form a perfect square number, and the yellow and dappled bulls together must form a triangular number. How many cattle are in the herd?
Reveal the answer
The smallest herd satisfying every condition has roughly 7.76 x 10^206,544 cattle — a number with over 206,000 digits, vastly more than the atoms in the observable universe. The poem was rediscovered in 1773 by G. E. Lessing in a manuscript at the Wolfenbuttel library and attributed to Archimedes. Georg Amthor worked out the solution's structure by hand in 1880, but the exact digits weren't computed until 1965, when a team at the University of Waterloo ran an IBM 7040 computer for over seven hours; the full decimal printout was finally published in 1981 after a Cray-1 reproduced it in just 10 minutes.