821536128 has 256 divisors, whose sum is σ = 2869056000. Its totient is φ = 226437120.

The previous prime is 821536109. The next prime is 821536139. The reversal of 821536128 is 821635128.

It is a happy number.

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 = 821536092 and 821536101.

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, 700983 + ... + 702153.

It is an arithmetic number, because the mean of its divisors is an integer number (11207250).

Almost surely, 2^821536128 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 821536128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1434528000).

821536128 is an abundant number, since it is smaller than the sum of its proper divisors (2047519872).

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

821536128 is a wasteful number, since it uses less digits than its factorization.

821536128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1230 (or 1212 counting only the distinct ones).

The product of its digits is 23040, while the sum is 36.

The square root of 821536128 is about 28662.4515350659. The cubic root of 821536128 is about 936.5742695522.

The spelling of 821536128 in words is "eight hundred twenty-one million, five hundred thirty-six thousand, one hundred twenty-eight".