28320728999 has 4 divisors (see below), whose sum is σ = 28321923336. Its totient is φ = 28319534664.

The previous prime is 28320728987. The next prime is 28320729079. The reversal of 28320728999 is 99982702382.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 99982702382 = 2 ⋅49991351191.

It is a cyclic number.

It is not a de Polignac number, because 28320728999 - 2⁸ = 28320728743 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28320728399) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 560864 + ... + 609269.

It is an arithmetic number, because the mean of its divisors is an integer number (7080480834).

Almost surely, 2^28320728999 is an apocalyptic number.

28320728999 is a deficient number, since it is larger than the sum of its proper divisors (1194337).

28320728999 is a wasteful number, since it uses less digits than its factorization.

28320728999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1194336.

The product of its (nonzero) digits is 7838208, while the sum is 59.

The spelling of 28320728999 in words is "twenty-eight billion, three hundred twenty million, seven hundred twenty-eight thousand, nine hundred ninety-nine".