81118387 has 4 divisors (see below), whose sum is σ = 92706736. Its totient is φ = 69530040.

The previous prime is 81118363. The next prime is 81118397. The reversal of 81118387 is 78381118.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81118387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81118327) 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, 5794164 + ... + 5794177.

It is an arithmetic number, because the mean of its divisors is an integer number (23176684).

Almost surely, 2^81118387 is an apocalyptic number.

81118387 is a deficient number, since it is larger than the sum of its proper divisors (11588349).

81118387 is a wasteful number, since it uses less digits than its factorization.

81118387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11588348.

The product of its digits is 10752, while the sum is 37.

The square root of 81118387 is about 9006.5746541069. The cubic root of 81118387 is about 432.8855630464.

The spelling of 81118387 in words is "eighty-one million, one hundred eighteen thousand, three hundred eighty-seven".