581666261 has 8 divisors (see below), whose sum is σ = 635580864. Its totient is φ = 527924320.

The previous prime is 581666249. The next prime is 581666291. The reversal of 581666261 is 162666185.

It is a happy number.

581666261 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 581666261 - 2²² = 577471957 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (581666201) 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, 36065 + ... + 49638.

It is an arithmetic number, because the mean of its divisors is an integer number (79447608).

Almost surely, 2^581666261 is an apocalyptic number.

It is an amenable number.

581666261 is a deficient number, since it is larger than the sum of its proper divisors (53914603).

581666261 is a wasteful number, since it uses less digits than its factorization.

581666261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86331.

The product of its digits is 103680, while the sum is 41.

The square root of 581666261 is about 24117.7582084239. The cubic root of 581666261 is about 834.7529411188.

The spelling of 581666261 in words is "five hundred eighty-one million, six hundred sixty-six thousand, two hundred sixty-one".