811923840 has 384 divisors, whose sum is σ = 3452904000. Its totient is φ = 171196416.

The previous prime is 811923823. The next prime is 811923857. The reversal of 811923840 is 48329118.

It is an interprime number because it is at equal distance from previous prime (811923823) and next prime (811923857).

It is a tau number, because it is divible by the number of its divisors (384).

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

It is a junction number, because it is equal to n+sod(n) for n = 811923795 and 811923804.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 523386 + ... + 524934.

Almost surely, 2^811923840 is an apocalyptic number.

811923840 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 811923840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1726452000).

811923840 is an abundant number, since it is smaller than the sum of its proper divisors (2640980160).

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

811923840 is a wasteful number, since it uses less digits than its factorization.

811923840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1594 (or 1579 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 811923840 is about 28494.2773201919. The cubic root of 811923840 is about 932.9071705218.

The spelling of 811923840 in words is "eight hundred eleven million, nine hundred twenty-three thousand, eight hundred forty".