18181989

素因数分解:

$3^6\times 7^2\times {\mathrm{509}}^1$

素因数の和:541

約数の個数: 42

約数和(自身を含む): 31773510

約数和(自身を除く): 13591521

約数列:

[1, 3, 7, 9, 21, 27, 49, 63, 81, 147, 189, 243, 441, 509, 567, 729, 1323, 1527, 1701, 3563, 3969, 4581, 5103, 10689, 11907, 13743, 24941, 32067, 35721, 41229, 74823, 96201, 123687, 224469, 288603, 371061, 673407, 865809, 2020221, 2597427, 6060663, 18181989]

約数ペア:

[(1, 18181989), (3, 6060663), (7, 2597427), (9, 2020221), (21, 865809), (27, 673407), (49, 371061), (63, 288603), (81, 224469), (147, 123687), (189, 96201), (243, 74823), (441, 41229), (509, 35721), (567, 32067), (729, 24941), (1323, 13743), (1527, 11907), (1701, 10689), (3563, 5103), (3969, 4581)]