20000000

素因数分解:

$2^8\times 5^7$

素因数の和:51

約数の個数: 72

約数和(自身を含む): 49902216

約数和(自身を除く): 29902216

約数列:

[1, 2, 4, 5, 8, 10, 16, 20, 25, 32, 40, 50, 64, 80, 100, 125, 128, 160, 200, 250, 256, 320, 400, 500, 625, 640, 800, 1000, 1250, 1280, 1600, 2000, 2500, 3125, 3200, 4000, 5000, 6250, 6400, 8000, 10000, 12500, 15625, 16000, 20000, 25000, 31250, 32000, 40000, 50000, 62500, 78125, 80000, 100000, 125000, 156250, 160000, 200000, 250000, 312500, 400000, 500000, 625000, 800000, 1000000, 1250000, 2000000, 2500000, 4000000, 5000000, 10000000, 20000000]

約数ペア:

[(1, 20000000), (2, 10000000), (4, 5000000), (5, 4000000), (8, 2500000), (10, 2000000), (16, 1250000), (20, 1000000), (25, 800000), (32, 625000), (40, 500000), (50, 400000), (64, 312500), (80, 250000), (100, 200000), (125, 160000), (128, 156250), (160, 125000), (200, 100000), (250, 80000), (256, 78125), (320, 62500), (400, 50000), (500, 40000), (625, 32000), (640, 31250), (800, 25000), (1000, 20000), (1250, 16000), (1280, 15625), (1600, 12500), (2000, 10000), (2500, 8000), (3125, 6400), (3200, 6250), (4000, 5000)]