11561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
It is a cyclic number.
It is a Duffinian number.
It is a nialpdrome in base 5 and base 11.
It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 11561.
211561 is an apocalyptic number.
11561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.
It is an amenable number.
11561 is a wasteful number, since it uses less digits than its factorization.
11561 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 1062.
The square root of 11561 is about 107.5220907535. The cubic root of 11561 is about 22.6116263566.
Subtracting 11561 from its reverse (16511), we obtain a triangular number (4950 = T99).
The spelling of 11561 in words is "eleven thousand, five hundred sixty-one".