820120820 has 12 divisors (see below), whose sum is σ = 1722253764. Its totient is φ = 328048320.

The previous prime is 820120793. The next prime is 820120823. The reversal of 820120820 is 28021028.

It can be written as a sum of positive squares in 2 ways, for example, as 527437156 + 292683664 = 22966^2 + 17108^2 .

It is a hoax number, since the sum of its digits (23) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820120823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20503001 + ... + 20503040.

It is an arithmetic number, because the mean of its divisors is an integer number (143521147).

Almost surely, 2^820120820 is an apocalyptic number.

It is an amenable number.

820120820 is an abundant number, since it is smaller than the sum of its proper divisors (902132944).

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

820120820 is a wasteful number, since it uses less digits than its factorization.

820120820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41006050 (or 41006048 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 23.

The square root of 820120820 is about 28637.7516575586. The cubic root of 820120820 is about 936.0361301100.

Adding to 820120820 its reverse (28021028), we get a palindrome (848141848).

The spelling of 820120820 in words is "eight hundred twenty million, one hundred twenty thousand, eight hundred twenty".