81565596 has 72 divisors (see below), whose sum is σ = 246007440. Its totient is φ = 23302944.

The previous prime is 81565573. The next prime is 81565607. The reversal of 81565596 is 69556518.

It is a happy number.

81565596 is a `hidden beast` number, since 8 + 1 + 56 + 5 + 596 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2415 + ... + 12998.

It is an arithmetic number, because the mean of its divisors is an integer number (3416770).

Almost surely, 2^81565596 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 81565596, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (123003720).

81565596 is an abundant number, since it is smaller than the sum of its proper divisors (164441844).

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

81565596 is a wasteful number, since it uses less digits than its factorization.

81565596 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15440 (or 15425 counting only the distinct ones).

The product of its digits is 324000, while the sum is 45.

The square root of 81565596 is about 9031.3673383381. The cubic root of 81565596 is about 433.6796109206.

The spelling of 81565596 in words is "eighty-one million, five hundred sixty-five thousand, five hundred ninety-six".