815904 has 36 divisors (see below), whose sum is σ = 2321046. Its totient is φ = 271872.

The previous prime is 815897. The next prime is 815923. The reversal of 815904 is 409518.

It can be written as a sum of positive squares in only one way, i.e., 725904 + 90000 = 852^2 + 300^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a nialpdrome in base 16.

It is a congruent number.

It is an unprimeable number.

815904 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 5 ways as a sum of consecutive naturals, for example, 1129 + ... + 1704.

2⁸¹⁵⁹⁰⁴ is an apocalyptic number.

It is an amenable number.

815904 is an abundant number, since it is smaller than the sum of its proper divisors (1505142).

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

815904 is a wasteful number, since it uses less digits than its factorization.

815904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2849 (or 2838 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 27.

The square root of 815904 is about 903.2740447948. The cubic root of 815904 is about 93.4429098518.

The spelling of 815904 in words is "eight hundred fifteen thousand, nine hundred four".