81336928 has 48 divisors (see below), whose sum is σ = 165533760. Its totient is φ = 39321216.

The previous prime is 81336911. The next prime is 81336943. The reversal of 81336928 is 82963318.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 126175 + ... + 126817.

It is an arithmetic number, because the mean of its divisors is an integer number (3448620).

Almost surely, 2^81336928 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 81336928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (82766880).

81336928 is an abundant number, since it is smaller than the sum of its proper divisors (84196832).

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

81336928 is a wasteful number, since it uses less digits than its factorization.

81336928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 779 (or 771 counting only the distinct ones).

The product of its digits is 62208, while the sum is 40.

The square root of 81336928 is about 9018.6987974985. The cubic root of 81336928 is about 433.2739600442.

The spelling of 81336928 in words is "eighty-one million, three hundred thirty-six thousand, nine hundred twenty-eight".