921808404 has 48 divisors (see below), whose sum is σ = 2607138240. Its totient is φ = 279335520.

The previous prime is 921808403. The next prime is 921808423. The reversal of 921808404 is 404808129.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (921808403) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 386779 + ... + 389154.

It is an arithmetic number, because the mean of its divisors is an integer number (54315380).

Almost surely, 2^921808404 is an apocalyptic number.

It is an amenable number.

921808404 is an abundant number, since it is smaller than the sum of its proper divisors (1685329836).

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

921808404 is a wasteful number, since it uses less digits than its factorization.

921808404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 775957 (or 775949 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The square root of 921808404 is about 30361.2977983485. The cubic root of 921808404 is about 973.2256676535.

The spelling of 921808404 in words is "nine hundred twenty-one million, eight hundred eight thousand, four hundred four".