81118919 has 8 divisors (see below), whose sum is σ = 92855808. Its totient is φ = 69419160.

The previous prime is 81118879. The next prime is 81118949. The reversal of 81118919 is 91981118.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81118919 - 2¹⁶ = 81053383 is a prime.

It is a super-2 number, since 2×81118919² = 13160558039457122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81118949) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4427 + ... + 13484.

It is an arithmetic number, because the mean of its divisors is an integer number (11606976).

Almost surely, 2^81118919 is an apocalyptic number.

81118919 is a deficient number, since it is larger than the sum of its proper divisors (11736889).

81118919 is a wasteful number, since it uses less digits than its factorization.

81118919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18565.

The product of its digits is 5184, while the sum is 38.

The square root of 81118919 is about 9006.6041880389. The cubic root of 81118919 is about 432.8865093778.

The spelling of 81118919 in words is "eighty-one million, one hundred eighteen thousand, nine hundred nineteen".