21278980

素因数分解:

$2^2\times 5^1\times {\mathrm{43}}^1\times {\mathrm{109}}^1\times {\mathrm{227}}^1$

素因数の和:388

約数の個数: 48

約数和(自身を含む): 46347840

約数和(自身を除く): 25068860

約数列:

[1, 2, 4, 5, 10, 20, 43, 86, 109, 172, 215, 218, 227, 430, 436, 454, 545, 860, 908, 1090, 1135, 2180, 2270, 4540, 4687, 9374, 9761, 18748, 19522, 23435, 24743, 39044, 46870, 48805, 49486, 93740, 97610, 98972, 123715, 195220, 247430, 494860, 1063949, 2127898, 4255796, 5319745, 10639490, 21278980]

約数ペア:

[(1, 21278980), (2, 10639490), (4, 5319745), (5, 4255796), (10, 2127898), (20, 1063949), (43, 494860), (86, 247430), (109, 195220), (172, 123715), (215, 98972), (218, 97610), (227, 93740), (430, 49486), (436, 48805), (454, 46870), (545, 39044), (860, 24743), (908, 23435), (1090, 19522), (1135, 18748), (2180, 9761), (2270, 9374), (4540, 4687)]