815491904 has 56 divisors (see below), whose sum is σ = 1753380288. Its totient is φ = 374814720.

The previous prime is 815491903. The next prime is 815491909. The reversal of 815491904 is 409194518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (815491903) 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 7 ways as a sum of consecutive naturals, for example, 38069 + ... + 55499.

Almost surely, 2^815491904 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 815491904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (876690144).

815491904 is an abundant number, since it is smaller than the sum of its proper divisors (937888384).

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

815491904 is a wasteful number, since it uses less digits than its factorization.

815491904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17503 (or 17493 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 41.

The square root of 815491904 is about 28556.8188704554. The cubic root of 815491904 is about 934.2717518440.

The spelling of 815491904 in words is "eight hundred fifteen million, four hundred ninety-one thousand, nine hundred four".