11585018581 has 4 divisors (see below), whose sum is σ = 11596063500. Its totient is φ = 11573973664.

The previous prime is 11585018567. The next prime is 11585018609. The reversal of 11585018581 is 18581058511.

11585018581 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18581058511 = 853 ⋅21783187.

It can be written as a sum of positive squares in 2 ways, for example, as 10243261681 + 1341756900 = 101209^2 + 36630^2 .

It is a cyclic number.

It is not a de Polignac number, because 11585018581 - 2¹⁵ = 11584985813 is a prime.

It is a super-2 number, since 2×11585018581² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11585018521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5520886 + ... + 5522983.

It is an arithmetic number, because the mean of its divisors is an integer number (2899015875).

Almost surely, 2^11585018581 is an apocalyptic number.

It is an amenable number.

11585018581 is a deficient number, since it is larger than the sum of its proper divisors (11044919).

11585018581 is a wasteful number, since it uses less digits than its factorization.

11585018581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11044918.

The product of its (nonzero) digits is 64000, while the sum is 43.

It can be divided in two parts, 115850 and 18581, that added together give a palindrome (134431).

The spelling of 11585018581 in words is "eleven billion, five hundred eighty-five million, eighteen thousand, five hundred eighty-one".