21257680

素因数分解:

$2^4\times 5^1\times {\mathrm{41}}^1\times {\mathrm{6481}}^1$

素因数の和:6535

約数の個数: 40

約数和(自身を含む): 50637384

約数和(自身を除く): 29379704

約数列:

[1, 2, 4, 5, 8, 10, 16, 20, 40, 41, 80, 82, 164, 205, 328, 410, 656, 820, 1640, 3280, 6481, 12962, 25924, 32405, 51848, 64810, 103696, 129620, 259240, 265721, 518480, 531442, 1062884, 1328605, 2125768, 2657210, 4251536, 5314420, 10628840, 21257680]

約数ペア:

[(1, 21257680), (2, 10628840), (4, 5314420), (5, 4251536), (8, 2657210), (10, 2125768), (16, 1328605), (20, 1062884), (40, 531442), (41, 518480), (80, 265721), (82, 259240), (164, 129620), (205, 103696), (328, 64810), (410, 51848), (656, 32405), (820, 25924), (1640, 12962), (3280, 6481)]