81536444078 has 16 divisors (see below), whose sum is σ = 130735001376. Its totient is φ = 38044575360.

The previous prime is 81536444057. The next prime is 81536444107. The reversal of 81536444078 is 87044463518.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21614351 + ... + 21618122.

It is an arithmetic number, because the mean of its divisors is an integer number (8170937586).

Almost surely, 2^81536444078 is an apocalyptic number.

81536444078 is a deficient number, since it is larger than the sum of its proper divisors (49198557298).

81536444078 is a wasteful number, since it uses less digits than its factorization.

81536444078 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43232539.

The product of its (nonzero) digits is 2580480, while the sum is 50.

The spelling of 81536444078 in words is "eighty-one billion, five hundred thirty-six million, four hundred forty-four thousand, seventy-eight".