81604573926 has 32 divisors (see below), whose sum is σ = 166813341408. Its totient is φ = 26604065280.

The previous prime is 81604573909. The next prime is 81604573931. The reversal of 81604573926 is 62937540618.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 303955 + ... + 505566.

It is an arithmetic number, because the mean of its divisors is an integer number (5212916919).

It is a 2-persistent number, because it is pandigital, and so is 2⋅81604573926 = 163209147852, but 3⋅81604573926 = 244813721778 is not.

Almost surely, 2^81604573926 is an apocalyptic number.

81604573926 is the 180671-st centered pentagonal number.

81604573926 is an abundant number, since it is smaller than the sum of its proper divisors (85208767482).

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

81604573926 is a wasteful number, since it uses less digits than its factorization.

81604573926 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 809896.

The product of its (nonzero) digits is 2177280, while the sum is 51.

The spelling of 81604573926 in words is "eighty-one billion, six hundred four million, five hundred seventy-three thousand, nine hundred twenty-six".