811345920 has 480 divisors, whose sum is σ = 3303387360. Its totient is φ = 168591360.

The previous prime is 811345901. The next prime is 811345939. The reversal of 811345920 is 29543118.

It is an interprime number because it is at equal distance from previous prime (811345901) and next prime (811345939).

It is a tau number, because it is divible by the number of its divisors (480).

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 73758715 + ... + 73758725.

It is an arithmetic number, because the mean of its divisors is an integer number (6882057).

Almost surely, 2^811345920 is an apocalyptic number.

811345920 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 811345920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1651693680).

811345920 is an abundant number, since it is smaller than the sum of its proper divisors (2492041440).

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

811345920 is an equidigital number, since it uses as much as digits as its factorization.

811345920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69 (or 28 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 811345920 is about 28484.1345313492. The cubic root of 811345920 is about 932.6857730393.

The spelling of 811345920 in words is "eight hundred eleven million, three hundred forty-five thousand, nine hundred twenty".