856840872 has 64 divisors (see below), whose sum is σ = 2282112000. Its totient is φ = 267309504.

The previous prime is 856840861. The next prime is 856840889. The reversal of 856840872 is 278048658.

It is a hoax number, since the sum of its digits (48) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26529 + ... + 49167.

It is an arithmetic number, because the mean of its divisors is an integer number (35658000).

Almost surely, 2^856840872 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 856840872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1141056000).

856840872 is an abundant number, since it is smaller than the sum of its proper divisors (1425271128).

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

856840872 is a wasteful number, since it uses less digits than its factorization.

856840872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22750 (or 22746 counting only the distinct ones).

The product of its (nonzero) digits is 860160, while the sum is 48.

The square root of 856840872 is about 29271.8443559677. The cubic root of 856840872 is about 949.8026818262.

The spelling of 856840872 in words is "eight hundred fifty-six million, eight hundred forty thousand, eight hundred seventy-two".