856809408 has 448 divisors, whose sum is σ = 3072384000. Its totient is φ = 204374016.

The previous prime is 856809397. The next prime is 856809413. The reversal of 856809408 is 804908658.

856809408 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (448).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 9627028 + ... + 9627116.

It is an arithmetic number, because the mean of its divisors is an integer number (6858000).

Almost surely, 2^856809408 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 856809408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1536192000).

856809408 is an abundant number, since it is smaller than the sum of its proper divisors (2215574592).

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

856809408 is a wasteful number, since it uses less digits than its factorization.

856809408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172 (or 162 counting only the distinct ones).

The product of its (nonzero) digits is 552960, while the sum is 48.

The square root of 856809408 is about 29271.3069062521. The cubic root of 856809408 is about 949.7910558023.

The spelling of 856809408 in words is "eight hundred fifty-six million, eight hundred nine thousand, four hundred eight".