81118917 has 48 divisors (see below), whose sum is σ = 136648512. Its totient is φ = 45826560.

The previous prime is 81118879. The next prime is 81118949. The reversal of 81118917 is 71981118.

It is a happy number.

It is not a de Polignac number, because 81118917 - 2⁷ = 81118789 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81118957) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 264078 + ... + 264384.

It is an arithmetic number, because the mean of its divisors is an integer number (2846844).

Almost surely, 2^81118917 is an apocalyptic number.

It is an amenable number.

81118917 is a deficient number, since it is larger than the sum of its proper divisors (55529595).

81118917 is a wasteful number, since it uses less digits than its factorization.

81118917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 498 (or 495 counting only the distinct ones).

The product of its digits is 4032, while the sum is 36.

The square root of 81118917 is about 9006.6040770093. The cubic root of 81118917 is about 432.8865058201.

The spelling of 81118917 in words is "eighty-one million, one hundred eighteen thousand, nine hundred seventeen".