The factors of the number 20,736,144 are: 1, 2, 3, 4, 6, 8, 9, 11, 12, 13, 16, 18, 19, 22, 24, 26, 33, 36, 38, 39, 44, 48, 52, 53, 57, 66, 72, 76, 78, 88, 99, 104, 106, 114, 117, 132, 143, 144, 152, 156, 159, 171, 176, 198, 208, 209, 212, 228, 234, 247, 264, 286, 304, 312, 318, 342, 396, 418, 424, 429, 456, 468, 477, 494, 528, 572, 583, 624, 627, 636, 684, 689, 741, 792, 836, 848, 858, 912, 936, 954, 988, 1007, 1144, 1166, 1254, 1272, 1287, 1368, 1378, 1482, 1584, 1672, 1716, 1749, 1872, 1881, 1908, 1976, 2014, 2067, 2223, 2288, 2332, 2508, 2544, 2574, 2717, 2736, 2756, 2964, 3021, 3344, 3432, 3498, 3762, 3816, 3952, 4028, 4134, 4446, 4664, 5016, 5148, 5247, 5434, 5512, 5928, 6042, 6201, 6864, 6996, 7524, 7579, 7632, 8056, 8151, 8268, 8892, 9063, 9328, 10032, 10296, 10494, 10868, 11024, 11077, 11856, 12084, 12402, 13091, 13992, 15048, 15158, 16112, 16302, 16536, 17784, 18126, 20592, 20988, 21736, 22154, 22737, 24168, 24453, 24804, 26182, 27984, 30096, 30316, 32604, 33072, 33231, 35568, 36252, 39273, 41976, 43472, 44308, 45474, 48336, 48906, 49608, 52364, 60632, 65208, 66462, 68211, 72504, 78546, 83952, 88616, 90948, 97812, 99216, 99693, 104728, 117819, 121264, 130416, 132924, 136422, 144001, 145008, 157092, 177232, 181896, 195624, 199386, 209456, 235638, 265848, 272844, 288002, 314184, 363792, 391248, 398772, 432003, 471276, 531696, 545688, 576004, 628368, 797544, 864006, 942552, 1091376, 1152008, 1296009, 1595088, 1728012, 1885104, 2304016, 2592018, 3456024, 5184036, 6912048, 10368072, 20736144.
If you add them up, you will get the total of 73,120,320.