11881 has 3 divisors (see below), whose sum is σ = 11991. Its totient is φ = 11772.

The previous prime is 11867. The next prime is 11887. The reversal of 11881 is 18811.

11881 = T₁₀₈ + T₁₀₉.

The square root of 11881 is 109.

It is a perfect power (a square), and thus also a powerful number.

11881 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is the 45-th star number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 18811 = 13 ⋅1447.

It can be written as a sum of positive squares in only one way, i.e., 8281 + 3600 = 91^2 + 60^2 .

It is not a de Polignac number, because 11881 - 2⁹ = 11369 is a prime.

It is a super-2 number, since 2×11881² = 282316322, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a plaindrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (11887) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 55 + ... + 163.

It is an arithmetic number, because the mean of its divisors is an integer number (3997).

2¹¹⁸⁸¹ is an apocalyptic number.

11881 is the 109-th square number.

11881 is the 55-th centered octagonal number.

It is an amenable number.

11881 is a deficient number, since it is larger than the sum of its proper divisors (110).

11881 is an frugal number, since it uses more digits than its factorization.

11881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218 (or 109 counting only the distinct ones).

The product of its digits is 64, while the sum is 19.

The cubic root of 11881 is about 22.8183549743.

Multiplying 11881 by its product of digits (64), we get a square (760384 = 872²).

The spelling of 11881 in words is "eleven thousand, eight hundred eighty-one".