640000

素因数分解:

$2^{10}\times 5^4$

素因数の和:40

約数の個数: 55

約数和(自身を含む): 1598707

約数和(自身を除く): 958707

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, 512, 625, 640, 800, 1000, 1024, 1250, 1280, 1600, 2000, 2500, 2560, 3200, 4000, 5000, 5120, 6400, 8000, 10000, 12800, 16000, 20000, 25600, 32000, 40000, 64000, 80000, 128000, 160000, 320000, 640000]

約数ペア:

[(1, 640000), (2, 320000), (4, 160000), (5, 128000), (8, 80000), (10, 64000), (16, 40000), (20, 32000), (25, 25600), (32, 20000), (40, 16000), (50, 12800), (64, 10000), (80, 8000), (100, 6400), (125, 5120), (128, 5000), (160, 4000), (200, 3200), (250, 2560), (256, 2500), (320, 2000), (400, 1600), (500, 1280), (512, 1250), (625, 1024), (640, 1000)]