821128320 has 512 divisors, whose sum is σ = 3187296000. Its totient is φ = 199065600.

The previous prime is 821128289. The next prime is 821128331. The reversal of 821128320 is 23821128.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 13461090 + ... + 13461150.

Almost surely, 2^821128320 is an apocalyptic number.

821128320 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 821128320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1593648000).

821128320 is an abundant number, since it is smaller than the sum of its proper divisors (2366167680).

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

821128320 is a wasteful number, since it uses less digits than its factorization.

821128320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149 (or 131 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 821128320 is about 28655.3366757398. The cubic root of 821128320 is about 936.4192730433.

Adding to 821128320 its reverse (23821128), we get a palindrome (844949448).

The spelling of 821128320 in words is "eight hundred twenty-one million, one hundred twenty-eight thousand, three hundred twenty".