The factors of the number 21,186,144 are: 1, 2, 3, 4, 6, 7, 8, 9, 12, 14, 16, 18, 21, 24, 27, 28, 31, 32, 36, 42, 48, 54, 56, 62, 63, 72, 84, 93, 96, 108, 112, 113, 124, 126, 144, 168, 186, 189, 216, 217, 224, 226, 248, 252, 279, 288, 336, 339, 372, 378, 432, 434, 452, 496, 504, 558, 651, 672, 678, 744, 756, 791, 837, 864, 868, 904, 992, 1008, 1017, 1116, 1302, 1356, 1488, 1512, 1582, 1674, 1736, 1808, 1953, 2016, 2034, 2232, 2373, 2604, 2712, 2976, 3024, 3051, 3164, 3348, 3472, 3503, 3616, 3906, 4068, 4464, 4746, 5208, 5424, 5859, 6048, 6102, 6328, 6696, 6944, 7006, 7119, 7812, 8136, 8928, 9492, 10416, 10509, 10848, 11718, 12204, 12656, 13392, 14012, 14238, 15624, 16272, 18984, 20832, 21018, 21357, 23436, 24408, 24521, 25312, 26784, 28024, 28476, 31248, 31527, 32544, 37968, 42036, 42714, 46872, 48816, 49042, 56048, 56952, 62496, 63054, 73563, 75936, 84072, 85428, 93744, 94581, 97632, 98084, 112096, 113904, 126108, 147126, 168144, 170856, 187488, 189162, 196168, 220689, 227808, 252216, 294252, 336288, 341712, 378324, 392336, 441378, 504432, 588504, 662067, 683424, 756648, 784672, 882756, 1008864, 1177008, 1324134, 1513296, 1765512, 2354016, 2648268, 3026592, 3531024, 5296536, 7062048, 10593072, 21186144.
If you add them up, you will get the total of 73,543,680.