28239396820 has 24 divisors (see below), whose sum is σ = 59447745000. Its totient is φ = 11268137472.

The previous prime is 28239396769. The next prime is 28239396853. The reversal of 28239396820 is 2869393282.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 2133885636 + 26105511184 = 46194^2 + 161572^2 .

It is a super-2 number, since 2×28239396820² (a number of 22 digits) 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 7 ways as a sum of consecutive naturals, for example, 1717945 + ... + 1734304.

It is an arithmetic number, because the mean of its divisors is an integer number (2476989375).

Almost surely, 2^28239396820 is an apocalyptic number.

28239396820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28239396820 is an abundant number, since it is smaller than the sum of its proper divisors (31208348180).

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

28239396820 is a wasteful number, since it uses less digits than its factorization.

28239396820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3452667 (or 3452665 counting only the distinct ones).

The product of its (nonzero) digits is 2239488, while the sum is 52.

The spelling of 28239396820 in words is "twenty-eight billion, two hundred thirty-nine million, three hundred ninety-six thousand, eight hundred twenty".