21185905

素因数分解:

$5^1\times {\mathrm{13}}^1\times {\mathrm{397}}^1\times {\mathrm{821}}^1$

素因数の和:1236

約数の個数: 16

約数和(自身を含む): 27481104

約数和(自身を除く): 6295199

約数列:

[1, 5, 13, 65, 397, 821, 1985, 4105, 5161, 10673, 25805, 53365, 325937, 1629685, 4237181, 21185905]

約数ペア:

[(1, 21185905), (5, 4237181), (13, 1629685), (65, 325937), (397, 53365), (821, 25805), (1985, 10673), (4105, 5161)]