856258561 has 4 divisors (see below), whose sum is σ = 856761300. Its totient is φ = 855755824.

The previous prime is 856258519. The next prime is 856258577. The reversal of 856258561 is 165852658.

It is a happy number.

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 124880625 + 731377936 = 11175^2 + 27044^2 .

It is a cyclic number.

It is not a de Polignac number, because 856258561 - 2⁹ = 856258049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (856259561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 248806 + ... + 252223.

It is an arithmetic number, because the mean of its divisors is an integer number (214190325).

Almost surely, 2^856258561 is an apocalyptic number.

It is an amenable number.

856258561 is a deficient number, since it is larger than the sum of its proper divisors (502739).

856258561 is a wasteful number, since it uses less digits than its factorization.

856258561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 502738.

The product of its digits is 576000, while the sum is 46.

The square root of 856258561 is about 29261.8960595516. The cubic root of 856258561 is about 949.5874703805.

The spelling of 856258561 in words is "eight hundred fifty-six million, two hundred fifty-eight thousand, five hundred sixty-one".