The factors of the number 1,620,528 are: 1, 2, 3, 4, 6, 7, 8, 12, 13, 14, 16, 21, 24, 26, 28, 39, 42, 48, 49, 52, 53, 56, 78, 84, 91, 98, 104, 106, 112, 147, 156, 159, 168, 182, 196, 208, 212, 273, 294, 312, 318, 336, 364, 371, 392, 424, 546, 588, 624, 636, 637, 689, 728, 742, 784, 848, 1092, 1113, 1176, 1272, 1274, 1378, 1456, 1484, 1911, 2067, 2184, 2226, 2352, 2544, 2548, 2597, 2756, 2968, 3822, 4134, 4368, 4452, 4823, 5096, 5194, 5512, 5936, 7644, 7791, 8268, 8904, 9646, 10192, 10388, 11024, 14469, 15288, 15582, 16536, 17808, 19292, 20776, 28938, 30576, 31164, 33072, 33761, 38584, 41552, 57876, 62328, 67522, 77168, 101283, 115752, 124656, 135044, 202566, 231504, 270088, 405132, 540176, 810264, 1620528.
If you add them up, you will get the total of 5,343,408.