81536 has 48 divisors (see below), whose sum is σ = 203490. Its totient is φ = 32256.

The previous prime is 81533. The next prime is 81547. The reversal of 81536 is 63518.

It can be written as a sum of positive squares in only one way, i.e., 78400 + 3136 = 280^2 + 56^2 .

It is not an unprimeable number, because it can be changed into a prime (81533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6266 + ... + 6278.

2⁸¹⁵³⁶ 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 81536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101745).

81536 is an abundant number, since it is smaller than the sum of its proper divisors (121954).

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

81536 is a wasteful number, since it uses less digits than its factorization.

81536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41 (or 22 counting only the distinct ones).

The product of its digits is 720, while the sum is 23.

The square root of 81536 is about 285.5450927612. The cubic root of 81536 is about 43.3627151162.

The spelling of 81536 in words is "eighty-one thousand, five hundred thirty-six".