820019564660 has 144 divisors (see below), whose sum is σ = 1896143364864. Its totient is φ = 297628649472.

The previous prime is 820019564659. The next prime is 820019564687. The reversal of 820019564660 is 66465910028.

It is a Harshad number since it is a multiple of its sum of digits (47).

It is a congruent number.

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 47 ways as a sum of consecutive naturals, for example, 18178694 + ... + 18223746.

It is an arithmetic number, because the mean of its divisors is an integer number (13167662256).

Almost surely, 2^820019564660 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 820019564660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (948071682432).

820019564660 is an abundant number, since it is smaller than the sum of its proper divisors (1076123800204).

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

820019564660 is a wasteful number, since it uses less digits than its factorization.

820019564660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45210 (or 45191 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 47.

The spelling of 820019564660 in words is "eight hundred twenty billion, nineteen million, five hundred sixty-four thousand, six hundred sixty".