The factors of the number 1,280,640 are: 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 20, 23, 24, 29, 30, 32, 40, 46, 48, 58, 60, 64, 69, 80, 87, 92, 96, 115, 116, 120, 128, 138, 145, 160, 174, 184, 192, 230, 232, 240, 276, 290, 320, 345, 348, 368, 384, 435, 460, 464, 480, 552, 580, 640, 667, 690, 696, 736, 870, 920, 928, 960, 1104, 1160, 1334, 1380, 1392, 1472, 1740, 1840, 1856, 1920, 2001, 2208, 2320, 2668, 2760, 2784, 2944, 3335, 3480, 3680, 3712, 4002, 4416, 4640, 5336, 5520, 5568, 6670, 6960, 7360, 8004, 8832, 9280, 10005, 10672, 11040, 11136, 13340, 13920, 14720, 16008, 18560, 20010, 21344, 22080, 26680, 27840, 32016, 40020, 42688, 44160, 53360, 55680, 64032, 80040, 85376, 106720, 128064, 160080, 213440, 256128, 320160, 426880, 640320, 1280640.
If you add them up, you will get the total of 1,280,643. Now subtract 1,280,640 to get 3,125,760