81328 has 40 divisors (see below), whose sum is σ = 187488. Its totient is φ = 33792.

The previous prime is 81307. The next prime is 81331. The reversal of 81328 is 82318.

It is a super-2 number, since 2×81328² = 13228487168, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81299 and 81308.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3525 + ... + 3547.

2⁸¹³²⁸ 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 81328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (93744).

81328 is an abundant number, since it is smaller than the sum of its proper divisors (106160).

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

81328 is a wasteful number, since it uses less digits than its factorization.

81328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61 (or 55 counting only the distinct ones).

The product of its digits is 384, while the sum is 22.

The square root of 81328 is about 285.1806445045. The cubic root of 81328 is about 43.3258106600.

Subtracting 81328 from its reverse (82318), we obtain a triangular number (990 = T₄₄).

It can be divided in two parts, 8132 and 8, that multiplied together give a palindrome (65056).

The spelling of 81328 in words is "eighty-one thousand, three hundred twenty-eight".