856417920 has 128 divisors (see below), whose sum is σ = 2750328000. Its totient is φ = 226664448.

The previous prime is 856417909. The next prime is 856417921. The reversal of 856417920 is 29714658.

It is a tau number, because it is divible by the number of its divisors (128).

It is not an unprimeable number, because it can be changed into a prime (856417921) by changing a digit.

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, 265276 + ... + 268484.

Almost surely, 2^856417920 is an apocalyptic number.

856417920 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 856417920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1375164000).

856417920 is an abundant number, since it is smaller than the sum of its proper divisors (1893910080).

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

856417920 is a wasteful number, since it uses less digits than its factorization.

856417920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3370 (or 3358 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 42.

The square root of 856417920 is about 29264.6189108965. The cubic root of 856417920 is about 949.6463762336.

The spelling of 856417920 in words is "eight hundred fifty-six million, four hundred seventeen thousand, nine hundred twenty".