856155520 has 128 divisors (see below), whose sum is σ = 2305428480. Its totient is φ = 301209600.

The previous prime is 856155493. The next prime is 856155539. The reversal of 856155520 is 25551658.

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

It is a self number, because there is not a number n which added to its sum of digits gives 856155520.

It is a congruent number.

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, 216279 + ... + 220201.

It is an arithmetic number, because the mean of its divisors is an integer number (18011160).

Almost surely, 2^856155520 is an apocalyptic number.

856155520 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 856155520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1152714240).

856155520 is an abundant number, since it is smaller than the sum of its proper divisors (1449272960).

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

856155520 is a wasteful number, since it uses less digits than its factorization.

856155520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3984 (or 3972 counting only the distinct ones).

The product of its (nonzero) digits is 60000, while the sum is 37.

The square root of 856155520 is about 29260.1353380329. The cubic root of 856155520 is about 949.5493781608.

The spelling of 856155520 in words is "eight hundred fifty-six million, one hundred fifty-five thousand, five hundred twenty".