The factors of the number 21,255,840 are: 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20, 24, 29, 30, 32, 36, 40, 45, 48, 58, 60, 72, 80, 87, 90, 96, 116, 120, 144, 145, 160, 174, 180, 232, 240, 261, 288, 290, 348, 360, 435, 464, 480, 509, 522, 580, 696, 720, 870, 928, 1018, 1044, 1160, 1305, 1392, 1440, 1527, 1740, 2036, 2088, 2320, 2545, 2610, 2784, 3054, 3480, 4072, 4176, 4581, 4640, 5090, 5220, 6108, 6960, 7635, 8144, 8352, 9162, 10180, 10440, 12216, 13920, 14761, 15270, 16288, 18324, 20360, 20880, 22905, 24432, 29522, 30540, 36648, 40720, 41760, 44283, 45810, 48864, 59044, 61080, 73296, 73805, 81440, 88566, 91620, 118088, 122160, 132849, 146592, 147610, 177132, 183240, 221415, 236176, 244320, 265698, 295220, 354264, 366480, 442830, 472352, 531396, 590440, 664245, 708528, 732960, 885660, 1062792, 1180880, 1328490, 1417056, 1771320, 2125584, 2361760, 2656980, 3542640, 4251168, 5313960, 7085280, 10627920, 21255840.
If you add them up, you will get the total of 75,184,200.