820128813 has 8 divisors (see below), whose sum is σ = 1249720128. Its totient is φ = 468645024.

The previous prime is 820128767. The next prime is 820128847. The reversal of 820128813 is 318821028.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 820128813 - 2⁹ = 820128301 is a prime.

It is a super-2 number, since 2×820128813² = 1345222539825577938, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820124813) 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 7 ways as a sum of consecutive naturals, for example, 19526856 + ... + 19526897.

It is an arithmetic number, because the mean of its divisors is an integer number (156215016).

Almost surely, 2^820128813 is an apocalyptic number.

It is an amenable number.

820128813 is a deficient number, since it is larger than the sum of its proper divisors (429591315).

820128813 is a wasteful number, since it uses less digits than its factorization.

820128813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39053763.

The product of its (nonzero) digits is 6144, while the sum is 33.

The square root of 820128813 is about 28637.8912107718. The cubic root of 820128813 is about 936.0391710084.

The spelling of 820128813 in words is "eight hundred twenty million, one hundred twenty-eight thousand, eight hundred thirteen".