581856 has 96 divisors (see below), whose sum is σ = 1814400. Its totient is φ = 161280.

The previous prime is 581843. The next prime is 581857. The reversal of 581856 is 658185.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (33).

It is an alternating number because its digits alternate between odd and even.

Its product of digits (9600) is a multiple of the sum of its prime divisors (64).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (581857) 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 15 ways as a sum of consecutive naturals, for example, 20050 + ... + 20078.

It is an arithmetic number, because the mean of its divisors is an integer number (18900).

2⁵⁸¹⁸⁵⁶ 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 581856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (907200).

581856 is an abundant number, since it is smaller than the sum of its proper divisors (1232544).

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

581856 is a wasteful number, since it uses less digits than its factorization.

581856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72 (or 64 counting only the distinct ones).

The product of its digits is 9600, while the sum is 33.

The square root of 581856 is about 762.7948610210. The cubic root of 581856 is about 83.4843696466.

The spelling of 581856 in words is "five hundred eighty-one thousand, eight hundred fifty-six".