821800320 has 256 divisors, whose sum is σ = 2887073280. Its totient is φ = 197181440.

The previous prime is 821800319. The next prime is 821800361. The reversal of 821800320 is 23008128.

821800320 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3526924 + ... + 3527156.

It is an arithmetic number, because the mean of its divisors is an integer number (11277630).

Almost surely, 2^821800320 is an apocalyptic number.

821800320 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 821800320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1443536640).

821800320 is an abundant number, since it is smaller than the sum of its proper divisors (2065272960).

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

821800320 is a wasteful number, since it uses less digits than its factorization.

821800320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 433 (or 421 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 821800320 is about 28667.0598422650. The cubic root of 821800320 is about 936.6746542268.

Adding to 821800320 its reverse (23008128), we get a palindrome (844808448).

The spelling of 821800320 in words is "eight hundred twenty-one million, eight hundred thousand, three hundred twenty".