81911039076 has 120 divisors (see below), whose sum is σ = 216855749880. Its totient is φ = 26958210048.

The previous prime is 81911039071. The next prime is 81911039101. The reversal of 81911039076 is 67093011918.

81911039076 is a `hidden beast` number, since 8 + 191 + 1 + 0 + 390 + 76 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 1385626176 + 80525412900 = 37224^2 + 283770^2 .

It is not an unprimeable number, because it can be changed into a prime (81911039071) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 9844470 + ... + 9852786.

It is an arithmetic number, because the mean of its divisors is an integer number (1807131249).

Almost surely, 2^81911039076 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81911039076, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108427874940).

81911039076 is an abundant number, since it is smaller than the sum of its proper divisors (134944710804).

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

81911039076 is a wasteful number, since it uses less digits than its factorization.

81911039076 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8715 (or 8704 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 45.

The spelling of 81911039076 in words is "eighty-one billion, nine hundred eleven million, thirty-nine thousand, seventy-six".