81111117 has 8 divisors (see below), whose sum is σ = 109517440. Its totient is φ = 53389440.

The previous prime is 81111101. The next prime is 81111119. The reversal of 81111117 is 71111118.

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

It is not a de Polignac number, because 81111117 - 2⁴ = 81111101 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81111093 and 81111102.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81111119) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 170884 + ... + 171357.

It is an arithmetic number, because the mean of its divisors is an integer number (13689680).

Almost surely, 2^81111117 is an apocalyptic number.

It is an amenable number.

81111117 is a deficient number, since it is larger than the sum of its proper divisors (28406323).

81111117 is a wasteful number, since it uses less digits than its factorization.

81111117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 342323.

The product of its digits is 56, while the sum is 21.

The square root of 81111117 is about 9006.1710510072. The cubic root of 81111117 is about 432.8726306227.

Subtracting from 81111117 its reverse (71111118), we obtain a palindrome (9999999).

It can be divided in two parts, 8111111 and 7, that added together give a palindrome (8111118).

The spelling of 81111117 in words is "eighty-one million, one hundred eleven thousand, one hundred seventeen".