21000

素因数分解:

$2^3\times 3^1\times 5^3\times 7^1$

素因数の和:31

約数の個数: 64

約数和(自身を含む): 74880

約数和(自身を除く): 53880

約数列:

[1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 15, 20, 21, 24, 25, 28, 30, 35, 40, 42, 50, 56, 60, 70, 75, 84, 100, 105, 120, 125, 140, 150, 168, 175, 200, 210, 250, 280, 300, 350, 375, 420, 500, 525, 600, 700, 750, 840, 875, 1000, 1050, 1400, 1500, 1750, 2100, 2625, 3000, 3500, 4200, 5250, 7000, 10500, 21000]

約数ペア:

[(1, 21000), (2, 10500), (3, 7000), (4, 5250), (5, 4200), (6, 3500), (7, 3000), (8, 2625), (10, 2100), (12, 1750), (14, 1500), (15, 1400), (20, 1050), (21, 1000), (24, 875), (25, 840), (28, 750), (30, 700), (35, 600), (40, 525), (42, 500), (50, 420), (56, 375), (60, 350), (70, 300), (75, 280), (84, 250), (100, 210), (105, 200), (120, 175), (125, 168), (140, 150)]