581031661 has 24 divisors (see below), whose sum is σ = 718589880. Its totient is φ = 466808832.

The previous prime is 581031653. The next prime is 581031677. The reversal of 581031661 is 166130185.

It can be written as a sum of positive squares in 4 ways, for example, as 60918025 + 520113636 = 7805^2 + 22806^2 .

It is not a de Polignac number, because 581031661 - 2³ = 581031653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (581031631) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 222781 + ... + 225373.

It is an arithmetic number, because the mean of its divisors is an integer number (29941245).

Almost surely, 2^581031661 is an apocalyptic number.

It is an amenable number.

581031661 is a deficient number, since it is larger than the sum of its proper divisors (137558219).

581031661 is a wasteful number, since it uses less digits than its factorization.

581031661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2893 (or 2886 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 581031661 is about 24104.5983372468. The cubic root of 581031661 is about 834.4492578236.

The spelling of 581031661 in words is "five hundred eighty-one million, thirty-one thousand, six hundred sixty-one".