Japanese coins, a plastic bag

2001

photo by Takagi Shigeki

cf. 17296 and 18416 are the third smallest amicable pair which Fermat found in 1636.

(Two numbers are called amicable if each equals to the sum of the divisors of the other.)

Divisors of 17296: 1 + 2 + 4 + 8 + 16 + 23 + 46 + 47 + 92 + 94 + 184 + 188 + 368 + 376 + 752 + 1081 + 2162 + 4324 + 8648 = 18416

Divisors of 18416: 1 + 2 + 4 + 8 + 16 + 1151 + 2302 + 4604 + 9208 = 17296