11565055661 has 12 divisors (see below), whose sum is σ = 12118696380. Its totient is φ = 11035738560.

The previous prime is 11565055631. The next prime is 11565055673. The reversal of 11565055661 is 16655056511.

It can be written as a sum of positive squares in 2 ways, for example, as 5166015625 + 6399040036 = 71875^2 + 79994^2 .

It is not a de Polignac number, because 11565055661 - 2³⁰ = 10491313837 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11565055631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 196745 + ... + 248673.

It is an arithmetic number, because the mean of its divisors is an integer number (1009891365).

Almost surely, 2^11565055661 is an apocalyptic number.

It is an amenable number.

11565055661 is a deficient number, since it is larger than the sum of its proper divisors (553640719).

11565055661 is an equidigital number, since it uses as much as digits as its factorization.

11565055661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52396 (or 52373 counting only the distinct ones).

The product of its (nonzero) digits is 135000, while the sum is 41.

The spelling of 11565055661 in words is "eleven billion, five hundred sixty-five million, fifty-five thousand, six hundred sixty-one".