400000

素因数分解:

$2^7\times 5^5$

素因数の和:39

約数の個数: 48

約数和(自身を含む): 996030

約数和(自身を除く): 596030

約数列:

[1, 2, 4, 5, 8, 10, 16, 20, 25, 32, 40, 50, 64, 80, 100, 125, 128, 160, 200, 250, 320, 400, 500, 625, 640, 800, 1000, 1250, 1600, 2000, 2500, 3125, 3200, 4000, 5000, 6250, 8000, 10000, 12500, 16000, 20000, 25000, 40000, 50000, 80000, 100000, 200000, 400000]

約数ペア:

[(1, 400000), (2, 200000), (4, 100000), (5, 80000), (8, 50000), (10, 40000), (16, 25000), (20, 20000), (25, 16000), (32, 12500), (40, 10000), (50, 8000), (64, 6250), (80, 5000), (100, 4000), (125, 3200), (128, 3125), (160, 2500), (200, 2000), (250, 1600), (320, 1250), (400, 1000), (500, 800), (625, 640)]