813856 has 24 divisors (see below), whose sum is σ = 1659420. Its totient is φ = 392448.

The previous prime is 813847. The next prime is 813863. The reversal of 813856 is 658318.

It can be written as a sum of positive squares in 2 ways, for example, as 781456 + 32400 = 884^2 + 180^2 .

It is an unprimeable number.

813856 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 3 ways as a sum of consecutive naturals, for example, 490 + ... + 1366.

2⁸¹³⁸⁵⁶ 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 813856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (829710).

813856 is an abundant number, since it is smaller than the sum of its proper divisors (845564).

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

813856 is a wasteful number, since it uses less digits than its factorization.

813856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 916 (or 908 counting only the distinct ones).

The product of its digits is 5760, while the sum is 31.

The square root of 813856 is about 902.1396787638. The cubic root of 813856 is about 93.3646606856.

The spelling of 813856 in words is "eight hundred thirteen thousand, eight hundred fifty-six".