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A239661
Divisors of 1089.
0
1, 3, 9, 11, 33, 99, 121, 363, 1089
OFFSET
1,2
COMMENTS
Divisors of 33^2.
The sum of divisors of 1089 is equal to 1729, the Hardy-Ramanujan number: A000203(1089) = A001235(1) = 1729.
The aliquot divisors of 1089 are also the powers of 3 written in base 26, see A004668.
Also 1089 is widely used in magic tricks because it can be produced from any two three-digit numbers (see Links section).
EXAMPLE
Sigma(1089) = 1 + 3 + 9 + 11 + 33 + 99 + 121 + 363 + 1089 = 1729.
MATHEMATICA
Divisors[1089] (* Wesley Ivan Hurt, Jun 13 2014 *)
PROG
(PARI) divisors(1089) \\ Michel Marcus, Jun 14 2014
CROSSREFS
KEYWORD
nonn,easy,fini,full
AUTHOR
Omar E. Pol, Jun 10 2014
STATUS
approved