21 is the number of demands which were sent to the Chinese government by the Japanese government of Okuma Shigenobu in 1915.
29 is the number of letters in the Turkish,Finnish, Swedish,Faroese,Danish and Norwegianalphabets.
31 is the number of flavors of Baskin-Robbins ice cream.
38 is the number of minutes in the shortest war in history in which Zanzibar surrendered to England in 1896.
41 is the number of members in the U.S. Senate needed to defeat a cloture vote and sustain a filibuster indefinitely.
42 is the number of kilometers in a marathon.
12 is the number of basic hues in the color wheel (3 primary colors (red, yellow, blue), 3 secondary colors (orange, green & purple) and 6 tertiary colors).