81009528 has 64 divisors (see below), whose sum is σ = 210816000. Its totient is φ = 25909632.

The previous prime is 81009527. The next prime is 81009547. The reversal of 81009528 is 82590018.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81009527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 166101 + ... + 166587.

It is an arithmetic number, because the mean of its divisors is an integer number (3294000).

Almost surely, 2^81009528 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 81009528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105408000).

81009528 is an abundant number, since it is smaller than the sum of its proper divisors (129806472).

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

81009528 is a wasteful number, since it uses less digits than its factorization.

81009528 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 764 (or 760 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 33.

The square root of 81009528 is about 9000.5293177679. The cubic root of 81009528 is about 432.6918355553.

The spelling of 81009528 in words is "eighty-one million, nine thousand, five hundred twenty-eight".