9855

Template:Short description Template:Infobox number 9855 (nine thousand eight hundred fifty-five) is the natural number following 9854 and preceding 9856.

In mathematics

It is the sum of all the numbers in any given row, column, or diagonal of the 27 × 27 magic square, as shown in the following calculation:

$9855=\frac{1}{27}\sum _{k=1}^{27^2}k=\frac{27\times (27^2+1)}{2}$

The 27 × 27 magic square contains 1 to 729, with 365 in the center.

9855 is also the number of days in 27 years; C.A. Brown hypothesized in a 1906 edition of The Monist that this number could have held a significance for Ancient Greeks as the "dividing line between the ages when men and women should begin to bear children to the State, 20-27 years for women, 27-34 years for men"