81928 has 48 divisors (see below), whose sum is σ = 205200. Its totient is φ = 30240.

The previous prime is 81919. The next prime is 81929. The reversal of 81928 is 82918.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 81896 and 81905.

It is not an unprimeable number, because it can be changed into a prime (81929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (3) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4303 + ... + 4321.

It is an arithmetic number, because the mean of its divisors is an integer number (4275).

2⁸¹⁹²⁸ is an apocalyptic number.

81928 is a gapful number since it is divisible by the number (88) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102600).

81928 is an abundant number, since it is smaller than the sum of its proper divisors (123272).

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

81928 is a wasteful number, since it uses less digits than its factorization.

81928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50 (or 39 counting only the distinct ones).

The product of its digits is 1152, while the sum is 28.

The square root of 81928 is about 286.2306762037. The cubic root of 81928 is about 43.4320955787.

81928 divided by its sum of digits (28) gives a triangular number (2926 = T₇₆).

Subtracting 81928 from its reverse (82918), we obtain a triangular number (990 = T₄₄).

It can be divided in two parts, 8192 and 8, that multiplied together give a 16-th power (65536 = 2¹⁶).

The spelling of 81928 in words is "eighty-one thousand, nine hundred twenty-eight".