81856240008 has 16 divisors (see below), whose sum is σ = 204640600080. Its totient is φ = 27285413328.

The previous prime is 81856239989. The next prime is 81856240033. The reversal of 81856240008 is 80004265818.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1705338310 + ... + 1705338357.

It is an arithmetic number, because the mean of its divisors is an integer number (12790037505).

Almost surely, 2^81856240008 is an apocalyptic number.

It is an amenable number.

81856240008 is an abundant number, since it is smaller than the sum of its proper divisors (122784360072).

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

81856240008 is a wasteful number, since it uses less digits than its factorization.

81856240008 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3410676676 (or 3410676672 counting only the distinct ones).

The product of its (nonzero) digits is 122880, while the sum is 42.

The spelling of 81856240008 in words is "eighty-one billion, eight hundred fifty-six million, two hundred forty thousand, eight".