11805581655 has 32 divisors (see below), whose sum is σ = 23985945600. Its totient is φ = 5396836896.

The previous prime is 11805581639. The next prime is 11805581699. The reversal of 11805581655 is 55618550811.

11805581655 is a `hidden beast` number, since 1 + 1 + 8 + 0 + 5 + 581 + 65 + 5 = 666.

It is not a de Polignac number, because 11805581655 - 2⁴ = 11805581639 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 11805581655.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6245395 + ... + 6247284.

It is an arithmetic number, because the mean of its divisors is an integer number (749560800).

Almost surely, 2^11805581655 is an apocalyptic number.

11805581655 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

11805581655 is an abundant number, since it is smaller than the sum of its proper divisors (12180363945).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

11805581655 is a wasteful number, since it uses less digits than its factorization.

11805581655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12492700 (or 12492694 counting only the distinct ones).

The product of its (nonzero) digits is 240000, while the sum is 45.

The spelling of 11805581655 in words is "eleven billion, eight hundred five million, five hundred eighty-one thousand, six hundred fifty-five".