811920 has 80 divisors (see below), whose sum is σ = 2678400. Its totient is φ = 202752.

The previous prime is 811919. The next prime is 811931. The reversal of 811920 is 29118.

It is a tau number, because it is divible by the number of its divisors (80).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3981 + ... + 4179.

It is an arithmetic number, because the mean of its divisors is an integer number (33480).

2⁸¹¹⁹²⁰ is an apocalyptic number.

811920 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 811920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1339200).

811920 is an abundant number, since it is smaller than the sum of its proper divisors (1866480).

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

811920 is a wasteful number, since it uses less digits than its factorization.

811920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 232 (or 226 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 21.

The square root of 811920 is about 901.0660353159. The cubic root of 811920 is about 93.2905699789.

The spelling of 811920 in words is "eight hundred eleven thousand, nine hundred twenty".