581991 has 8 divisors (see below), whose sum is σ = 779520. Its totient is φ = 386232.

The previous prime is 581983. The next prime is 582011. The reversal of 581991 is 199185.

581991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 581991 - 2³ = 581983 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (581921) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1026 + ... + 1488.

It is an arithmetic number, because the mean of its divisors is an integer number (97440).

2⁵⁸¹⁹⁹¹ is an apocalyptic number.

581991 is a deficient number, since it is larger than the sum of its proper divisors (197529).

581991 is a wasteful number, since it uses less digits than its factorization.

581991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 885.

The product of its digits is 3240, while the sum is 33.

The square root of 581991 is about 762.8833462594. The cubic root of 581991 is about 83.4908257218.

The spelling of 581991 in words is "five hundred eighty-one thousand, nine hundred ninety-one".