The factors of the number 644,665,320 are: 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 13, 15, 18, 20, 24, 26, 30, 36, 39, 40, 45, 52, 60, 65, 72, 78, 90, 104, 117, 120, 130, 139, 156, 180, 195, 234, 260, 278, 312, 360, 390, 417, 468, 520, 556, 585, 695, 780, 834, 936, 991, 1112, 1170, 1251, 1390, 1560, 1668, 1807, 1982, 2085, 2340, 2502, 2780, 2973, 3336, 3614, 3964, 4170, 4680, 4955, 5004, 5421, 5560, 5946, 6255, 7228, 7928, 8340, 8919, 9035, 9910, 10008, 10842, 11892, 12510, 12883, 14456, 14865, 16263, 16680, 17838, 18070, 19820, 21684, 23784, 25020, 25766, 27105, 29730, 32526, 35676, 36140, 38649, 39640, 43368, 44595, 50040, 51532, 54210, 59460, 64415, 65052, 71352, 72280, 77298, 81315, 89190, 103064, 108420, 115947, 118920, 128830, 130104, 137749, 154596, 162630, 178380, 193245, 216840, 231894, 257660, 275498, 309192, 325260, 356760, 386490, 413247, 463788, 515320, 550996, 579735, 650520, 688745, 772980, 826494, 927576, 1101992, 1159470, 1239741, 1377490, 1545960, 1652988, 1790737, 2066235, 2318940, 2479482, 2754980, 3305976, 3581474, 4132470, 4637880, 4958964, 5372211, 5509960, 6198705, 7162948, 8264940, 8953685, 9917928, 10744422, 12397410, 14325896, 16116633, 16529880, 17907370, 21488844, 24794820, 26861055, 32233266, 35814740, 42977688, 49589640, 53722110, 64466532, 71629480, 80583165, 107444220, 128933064, 161166330, 214888440, 322332660, 644665320.
If you add them up, you will get the total of 644,665,321. Now subtract 644,665,320 to get 1,630,189,080