820421820 has 72 divisors (see below), whose sum is σ = 2568908160. Its totient is φ = 211720320.

The previous prime is 820421813. The next prime is 820421837. The reversal of 820421820 is 28124028.

820421820 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×820421820² = 1346183925464224800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 67935 + ... + 79094.

It is an arithmetic number, because the mean of its divisors is an integer number (35679280).

Almost surely, 2^820421820 is an apocalyptic number.

It is an amenable number.

820421820 is an abundant number, since it is smaller than the sum of its proper divisors (1748486340).

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

820421820 is a wasteful number, since it uses less digits than its factorization.

820421820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147075 (or 147070 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 27.

The square root of 820421820 is about 28643.0064762762. The cubic root of 820421820 is about 936.1506304805.

Adding to 820421820 its reverse (28124028), we get a palindrome (848545848).

The spelling of 820421820 in words is "eight hundred twenty million, four hundred twenty-one thousand, eight hundred twenty".