21780009

素因数分解:

$3^4\times {\mathrm{17}}^1\times {\mathrm{15817}}^1$

素因数の和:15846

約数の個数: 20

約数和(自身を含む): 34451604

約数和(自身を除く): 12671595

約数列:

[1, 3, 9, 17, 27, 51, 81, 153, 459, 1377, 15817, 47451, 142353, 268889, 427059, 806667, 1281177, 2420001, 7260003, 21780009]

約数ペア:

[(1, 21780009), (3, 7260003), (9, 2420001), (17, 1281177), (27, 806667), (51, 427059), (81, 268889), (153, 142353), (459, 47451), (1377, 15817)]