81118331 has 4 divisors (see below), whose sum is σ = 92706672. Its totient is φ = 69529992.

The previous prime is 81118327. The next prime is 81118337. The reversal of 81118331 is 13381118.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13381118 = 2 ⋅6690559.

It is not a de Polignac number, because 81118331 - 2² = 81118327 is a prime.

It is a super-2 number, since 2×81118331² = 13160367248451122, which contains 22 as substring.

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 81118331.

It is not an unprimeable number, because it can be changed into a prime (81118337) 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, 5794160 + ... + 5794173.

It is an arithmetic number, because the mean of its divisors is an integer number (23176668).

Almost surely, 2^81118331 is an apocalyptic number.

81118331 is a deficient number, since it is larger than the sum of its proper divisors (11588341).

81118331 is a wasteful number, since it uses less digits than its factorization.

81118331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11588340.

The product of its digits is 576, while the sum is 26.

The square root of 81118331 is about 9006.5715452663. The cubic root of 81118331 is about 432.8854634324.

Adding to 81118331 its reverse (13381118), we get a palindrome (94499449).

The spelling of 81118331 in words is "eighty-one million, one hundred eighteen thousand, three hundred thirty-one".