856561128 has 16 divisors (see below), whose sum is σ = 2141402880. Its totient is φ = 285520368.

The previous prime is 856561087. The next prime is 856561129. The reversal of 856561128 is 821165658.

It is a self number, because there is not a number n which added to its sum of digits gives 856561128.

It is not an unprimeable number, because it can be changed into a prime (856561129) 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, 17845000 + ... + 17845047.

It is an arithmetic number, because the mean of its divisors is an integer number (133837680).

Almost surely, 2^856561128 is an apocalyptic number.

It is an amenable number.

856561128 is an abundant number, since it is smaller than the sum of its proper divisors (1284841752).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

856561128 is a wasteful number, since it uses less digits than its factorization.

856561128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35690056 (or 35690052 counting only the distinct ones).

The product of its digits is 115200, while the sum is 42.

The square root of 856561128 is about 29267.0655857399. The cubic root of 856561128 is about 949.6993057576.

The spelling of 856561128 in words is "eight hundred fifty-six million, five hundred sixty-one thousand, one hundred twenty-eight".