81928928 has 12 divisors (see below), whose sum is σ = 161297640. Its totient is φ = 40964448.

The previous prime is 81928927. The next prime is 81928949. The reversal of 81928928 is 82982918.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81928927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1280108 + ... + 1280171.

It is an arithmetic number, because the mean of its divisors is an integer number (13441470).

Almost surely, 2^81928928 is an apocalyptic number.

It is an amenable number.

81928928 is a deficient number, since it is larger than the sum of its proper divisors (79368712).

81928928 is a wasteful number, since it uses less digits than its factorization.

81928928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2560289 (or 2560281 counting only the distinct ones).

The product of its digits is 165888, while the sum is 47.

The square root of 81928928 is about 9051.4599927305. The cubic root of 81928928 is about 434.3225956344.

The spelling of 81928928 in words is "eighty-one million, nine hundred twenty-eight thousand, nine hundred twenty-eight".