11581855 has 4 divisors (see below), whose sum is σ = 13898232. Its totient is φ = 9265480.

The previous prime is 11581853. The next prime is 11581901. The reversal of 11581855 is 55818511.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 55818511 = 7 ⋅7974073.

It is not a de Polignac number, because 11581855 - 2¹ = 11581853 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 11581855.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11581853) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1158181 + ... + 1158190.

It is an arithmetic number, because the mean of its divisors is an integer number (3474558).

Almost surely, 2^11581855 is an apocalyptic number.

11581855 is a deficient number, since it is larger than the sum of its proper divisors (2316377).

11581855 is an equidigital number, since it uses as much as digits as its factorization.

11581855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2316376.

The product of its digits is 8000, while the sum is 34.

The square root of 11581855 is about 3403.2124529626. The cubic root of 11581855 is about 226.2521463325.

The spelling of 11581855 in words is "eleven million, five hundred eighty-one thousand, eight hundred fifty-five".