11556 has 24 divisors (see below), whose sum is σ = 30240. Its totient is φ = 3816.

The previous prime is 11551. The next prime is 11579. The reversal of 11556 is 65511.

11556 is an esthetic number in base 7, because in such base its adjacent digits differ by 1.

It is a super-2 number, since 2×11556² = 267082272, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a plaindrome in base 10.

It is a nialpdrome in base 5.

It is a zygodrome in base 5.

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

11556 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55 + ... + 161.

It is an arithmetic number, because the mean of its divisors is an integer number (1260).

2¹¹⁵⁵⁶ is an apocalyptic number.

It is a pronic number, being equal to 107×108.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 11556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15120).

11556 is an abundant number, since it is smaller than the sum of its proper divisors (18684).

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

11556 is a wasteful number, since it uses less digits than its factorization.

11556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120 (or 112 counting only the distinct ones).

The product of its digits is 150, while the sum is 18.

The square root of 11556 is about 107.4988372030. The cubic root of 11556 is about 22.6083661302.

It can be divided in two parts, 115 and 56, that added together give a palindrome (171).

The spelling of 11556 in words is "eleven thousand, five hundred fifty-six".