81157111818 has 16 divisors (see below), whose sum is σ = 171862119360. Its totient is φ = 25461054656.

The previous prime is 81157111811. The next prime is 81157111843. The reversal of 81157111818 is 81811175118.

It is a self number, because there is not a number n which added to its sum of digits gives 81157111818.

It is not an unprimeable number, because it can be changed into a prime (81157111811) 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, 397828878 + ... + 397829081.

It is an arithmetic number, because the mean of its divisors is an integer number (10741382460).

Almost surely, 2^81157111818 is an apocalyptic number.

81157111818 is an abundant number, since it is smaller than the sum of its proper divisors (90705007542).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81157111818 is a wasteful number, since it uses less digits than its factorization.

81157111818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 795657981.

The product of its digits is 17920, while the sum is 42.

The spelling of 81157111818 in words is "eighty-one billion, one hundred fifty-seven million, one hundred eleven thousand, eight hundred eighteen".