20500000

素因数分解:

$2^5\times 5^6\times {\mathrm{41}}^1$

素因数の和:81

約数の個数: 84

約数和(自身を含む): 51679026

約数和(自身を除く): 31179026

約数列:

[1, 2, 4, 5, 8, 10, 16, 20, 25, 32, 40, 41, 50, 80, 82, 100, 125, 160, 164, 200, 205, 250, 328, 400, 410, 500, 625, 656, 800, 820, 1000, 1025, 1250, 1312, 1640, 2000, 2050, 2500, 3125, 3280, 4000, 4100, 5000, 5125, 6250, 6560, 8200, 10000, 10250, 12500, 15625, 16400, 20000, 20500, 25000, 25625, 31250, 32800, 41000, 50000, 51250, 62500, 82000, 100000, 102500, 125000, 128125, 164000, 205000, 250000, 256250, 410000, 500000, 512500, 640625, 820000, 1025000, 1281250, 2050000, 2562500, 4100000, 5125000, 10250000, 20500000]

約数ペア:

[(1, 20500000), (2, 10250000), (4, 5125000), (5, 4100000), (8, 2562500), (10, 2050000), (16, 1281250), (20, 1025000), (25, 820000), (32, 640625), (40, 512500), (41, 500000), (50, 410000), (80, 256250), (82, 250000), (100, 205000), (125, 164000), (160, 128125), (164, 125000), (200, 102500), (205, 100000), (250, 82000), (328, 62500), (400, 51250), (410, 50000), (500, 41000), (625, 32800), (656, 31250), (800, 25625), (820, 25000), (1000, 20500), (1025, 20000), (1250, 16400), (1312, 15625), (1640, 12500), (2000, 10250), (2050, 10000), (2500, 8200), (3125, 6560), (3280, 6250), (4000, 5125), (4100, 5000)]