891491904 has 84 divisors (see below), whose sum is σ = 2591409600. Its totient is φ = 292965120.

The previous prime is 891491873. The next prime is 891491981. The reversal of 891491904 is 409194198.

It is a self number, because there is not a number n which added to its sum of digits gives 891491904.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 29997 + ... + 51795.

Almost surely, 2^891491904 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 891491904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1295704800).

891491904 is an abundant number, since it is smaller than the sum of its proper divisors (1699917696).

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

891491904 is a wasteful number, since it uses less digits than its factorization.

891491904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21888 (or 21875 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 45.

The square root of 891491904 is about 29857.8616782917. The cubic root of 891491904 is about 962.4373482354.

The spelling of 891491904 in words is "eight hundred ninety-one million, four hundred ninety-one thousand, nine hundred four".