20991789

素因数分解:

$3^2\times 7^1\times {\mathrm{13}}^1\times {\mathrm{19}}^2\times {\mathrm{71}}^1$

素因数の和:135

約数の個数: 72

約数和(自身を含む): 39940992

約数和(自身を除く): 18949203

約数列:

[1, 3, 7, 9, 13, 19, 21, 39, 57, 63, 71, 91, 117, 133, 171, 213, 247, 273, 361, 399, 497, 639, 741, 819, 923, 1083, 1197, 1349, 1491, 1729, 2223, 2527, 2769, 3249, 4047, 4473, 4693, 5187, 6461, 7581, 8307, 9443, 12141, 14079, 15561, 17537, 19383, 22743, 25631, 28329, 32851, 42237, 52611, 58149, 76893, 84987, 98553, 122759, 157833, 179417, 230679, 295659, 333203, 368277, 538251, 999609, 1104831, 1614753, 2332421, 2998827, 6997263, 20991789]

約数ペア:

[(1, 20991789), (3, 6997263), (7, 2998827), (9, 2332421), (13, 1614753), (19, 1104831), (21, 999609), (39, 538251), (57, 368277), (63, 333203), (71, 295659), (91, 230679), (117, 179417), (133, 157833), (171, 122759), (213, 98553), (247, 84987), (273, 76893), (361, 58149), (399, 52611), (497, 42237), (639, 32851), (741, 28329), (819, 25631), (923, 22743), (1083, 19383), (1197, 17537), (1349, 15561), (1491, 14079), (1729, 12141), (2223, 9443), (2527, 8307), (2769, 7581), (3249, 6461), (4047, 5187), (4473, 4693)]