581531161 has 4 divisors (see below), whose sum is σ = 585776052. Its totient is φ = 577286272.

The previous prime is 581531147. The next prime is 581531177. The reversal of 581531161 is 161135185.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 130393561 + 451137600 = 11419^2 + 21240^2 .

It is a cyclic number.

It is not a de Polignac number, because 581531161 - 2²³ = 573142553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (581531101) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2122240 + ... + 2122513.

It is an arithmetic number, because the mean of its divisors is an integer number (146444013).

Almost surely, 2^581531161 is an apocalyptic number.

It is an amenable number.

581531161 is a deficient number, since it is larger than the sum of its proper divisors (4244891).

581531161 is a wasteful number, since it uses less digits than its factorization.

581531161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4244890.

The product of its digits is 3600, while the sum is 31.

The square root of 581531161 is about 24114.9572050211. The cubic root of 581531161 is about 834.6883084923.

The spelling of 581531161 in words is "five hundred eighty-one million, five hundred thirty-one thousand, one hundred sixty-one".