815856 has 40 divisors (see below), whose sum is σ = 2202240. Its totient is φ = 259776.

The previous prime is 815851. The next prime is 815869. The reversal of 815856 is 658518.

815856 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (815851) by changing a digit.

815856 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 735 + ... + 1473.

It is an arithmetic number, because the mean of its divisors is an integer number (55056).

2⁸¹⁵⁸⁵⁶ 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 815856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1101120).

815856 is an abundant number, since it is smaller than the sum of its proper divisors (1386384).

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

815856 is a wasteful number, since it uses less digits than its factorization.

815856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 773 (or 767 counting only the distinct ones).

The product of its digits is 9600, while the sum is 33.

The square root of 815856 is about 903.2474743945. The cubic root of 815856 is about 93.4410773864.

The spelling of 815856 in words is "eight hundred fifteen thousand, eight hundred fifty-six".