11555116561 has 8 divisors (see below), whose sum is σ = 11676438144. Its totient is φ = 11433840000.

The previous prime is 11555116543. The next prime is 11555116567. The reversal of 11555116561 is 16561155511.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 11555116561 - 2²³ = 11546727953 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 11555116561.

It is not an unprimeable number, because it can be changed into a prime (11555116567) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 833436 + ... + 847186.

It is an arithmetic number, because the mean of its divisors is an integer number (1459554768).

Almost surely, 2^11555116561 is an apocalyptic number.

It is an amenable number.

11555116561 is a deficient number, since it is larger than the sum of its proper divisors (121321583).

11555116561 is an equidigital number, since it uses as much as digits as its factorization.

11555116561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22511.

The product of its digits is 22500, while the sum is 37.

The spelling of 11555116561 in words is "eleven billion, five hundred fifty-five million, one hundred sixteen thousand, five hundred sixty-one".