821304908820 has 576 divisors, whose sum is σ = 2910169866240. Its totient is φ = 185288601600.

The previous prime is 821304908819. The next prime is 821304908843. The reversal of 821304908820 is 28809403128.

821304908820 is a `hidden beast` number, since 8 + 2 + 130 + 490 + 8 + 8 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 1632812689 + ... + 1632813191.

It is an arithmetic number, because the mean of its divisors is an integer number (5052378240).

Almost surely, 2^821304908820 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 821304908820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1455084933120).

821304908820 is an abundant number, since it is smaller than the sum of its proper divisors (2088864957420).

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

821304908820 is a wasteful number, since it uses less digits than its factorization.

821304908820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 996 (or 991 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 45.

The spelling of 821304908820 in words is "eight hundred twenty-one billion, three hundred four million, nine hundred eight thousand, eight hundred twenty".