821804428836 has 96 divisors (see below), whose sum is σ = 2145806933760. Its totient is φ = 271982016000.

The previous prime is 821804428807. The next prime is 821804428849. The reversal of 821804428836 is 638824408128.

821804428836 is a `hidden beast` number, since 8 + 2 + 180 + 4 + 428 + 8 + 36 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 34903660 + ... + 34927196.

It is an arithmetic number, because the mean of its divisors is an integer number (22352155560).

Almost surely, 2^821804428836 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 821804428836, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1072903466880).

821804428836 is an abundant number, since it is smaller than the sum of its proper divisors (1324002504924).

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

821804428836 is a wasteful number, since it uses less digits than its factorization.

821804428836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25842 (or 25834 counting only the distinct ones).

The product of its (nonzero) digits is 4718592, while the sum is 54.

The spelling of 821804428836 in words is "eight hundred twenty-one billion, eight hundred four million, four hundred twenty-eight thousand, eight hundred thirty-six".