11555 has 4 divisors (see below), whose sum is σ = 13872. Its totient is φ = 9240.

The previous prime is 11551. The next prime is 11579. The reversal of 11555 is 55511.

11555 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.

It is not a de Polignac number, because 11555 - 2² = 11551 is a prime.

It is a nude number because it is divisible by every one of its digits.

It is a Duffinian number.

It is a plaindrome in base 10.

It is a nialpdrome in base 5 and base 11.

It is a zygodrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (11551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1151 + ... + 1160.

It is an arithmetic number, because the mean of its divisors is an integer number (3468).

2¹¹⁵⁵⁵ is an apocalyptic number.

11555 is a deficient number, since it is larger than the sum of its proper divisors (2317).

11555 is an equidigital number, since it uses as much as digits as its factorization.

11555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2316.

The product of its digits is 125, while the sum is 17.

The square root of 11555 is about 107.4941858893. The cubic root of 11555 is about 22.6077139720.

Subtracting 11555 from its reverse (55511), we obtain a triangular number (43956 = T₂₉₆).

It can be divided in two parts, 1155 and 5, that multiplied together give a palindrome (5775).

The spelling of 11555 in words is "eleven thousand, five hundred fifty-five".