81589 has 4 divisors (see below), whose sum is σ = 82656. Its totient is φ = 80524.

The previous prime is 81569. The next prime is 81611. The reversal of 81589 is 98518.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81589 - 2⁹ = 81077 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81589.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81509) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 409 + ... + 574.

It is an arithmetic number, because the mean of its divisors is an integer number (20664).

2⁸¹⁵⁸⁹ is an apocalyptic number.

It is an amenable number.

81589 is a deficient number, since it is larger than the sum of its proper divisors (1067).

81589 is an equidigital number, since it uses as much as digits as its factorization.

81589 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1066.

The product of its digits is 2880, while the sum is 31.

The square root of 81589 is about 285.6378826416. The cubic root of 81589 is about 43.3721086197.

The spelling of 81589 in words is "eighty-one thousand, five hundred eighty-nine".