Unique integers can be expressed as mn and nm (when both m and n are integers), and 42=24. Because 22=2×2, it has this feature. Also equal to 22? . The third central pentagonal number. And 15 form a pair of Ruth Allen numbers. Hexadecimal is often used in computer systems. 446,286 Any number divisible by 16 can be divisible without cycle. (Any number with only 2 and 5 divisible by a prime factor can be divisible without cycle) Power number116 2256 34,096 465,536 51,048,576 616,777,2/kloc. 296 968,7 19,476,736 10 1,099,5 1 1,627,776 1 1 17,592, 186,044, 4 16 1228 1,474,976, 7 10,656 134,503,599,627,370,496 1472,057,594,037,927, 936 15 1 15292 1504606,846,976 16 18,446,744,073, 709,55 1,6 16 17295, 147,905, 179,352,825,856 184,722,366,482,869,645,2 13,696 1975,557,863,725,9 14,323, 4 19, 13620 1, 208,925,8 19,6 14,629, 174,706, 1762 1 19,342,8 13, 1 13,834,066,795,298, 8 1622309,485,009,82 1,345,068,724,78 1,056234,95 1,760, 157, 14 1,52 1,099,596,496,8962479, 228, 162, 5 14,264,337,593,543,950,33625 1,267,650,600,228,229,40 1,496,703,205,376……