820844868020 has 12 divisors (see below), whose sum is σ = 1723774222884. Its totient is φ = 328337947200.

The previous prime is 820844868013. The next prime is 820844868073. The reversal of 820844868020 is 20868448028.

It can be written as a sum of positive squares in 2 ways, for example, as 222035094436 + 598809773584 = 471206^2 + 773828^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 820844868020.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20521121681 + ... + 20521121720.

It is an arithmetic number, because the mean of its divisors is an integer number (143647851907).

Almost surely, 2^820844868020 is an apocalyptic number.

It is an amenable number.

820844868020 is an abundant number, since it is smaller than the sum of its proper divisors (902929354864).

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

820844868020 is a wasteful number, since it uses less digits than its factorization.

820844868020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41042243410 (or 41042243408 counting only the distinct ones).

The product of its (nonzero) digits is 1572864, while the sum is 50.

The spelling of 820844868020 in words is "eight hundred twenty billion, eight hundred forty-four million, eight hundred sixty-eight thousand, twenty".