28320813172 has 24 divisors (see below), whose sum is σ = 49780450440. Its totient is φ = 14097914880.

The previous prime is 28320813167. The next prime is 28320813173. The reversal of 28320813172 is 27131802382.

It can be written as a sum of positive squares in 4 ways, for example, as 12455899236 + 15864913936 = 111606^2 + 125956^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28320813173) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1380204 + ... + 1400572.

It is an arithmetic number, because the mean of its divisors is an integer number (2074185435).

Almost surely, 2^28320813172 is an apocalyptic number.

It is an amenable number.

28320813172 is a deficient number, since it is larger than the sum of its proper divisors (21459637268).

28320813172 is a wasteful number, since it uses less digits than its factorization.

28320813172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21891 (or 21889 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 37.

The spelling of 28320813172 in words is "twenty-eight billion, three hundred twenty million, eight hundred thirteen thousand, one hundred seventy-two".