19978721

素因数分解:

$7^4\times {\mathrm{53}}^1\times {\mathrm{157}}^1$

素因数の和:238

約数の個数: 20

約数和(自身を含む): 23898132

約数和(自身を除く): 3919411

約数列:

[1, 7, 49, 53, 157, 343, 371, 1099, 2401, 2597, 7693, 8321, 18179, 53851, 58247, 127253, 376957, 407729, 2854103, 19978721]

約数ペア:

[(1, 19978721), (7, 2854103), (49, 407729), (53, 376957), (157, 127253), (343, 58247), (371, 53851), (1099, 18179), (2401, 8321), (2597, 7693)]