28320399 has 12 divisors (see below), whose sum is σ = 41270736. Its totient is φ = 18712512.

The previous prime is 28320373. The next prime is 28320403. The reversal of 28320399 is 99302382.

It is not a de Polignac number, because 28320399 - 2¹¹ = 28318351 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28320319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12907 + ... + 14940.

It is an arithmetic number, because the mean of its divisors is an integer number (3439228).

Almost surely, 2^28320399 is an apocalyptic number.

28320399 is a deficient number, since it is larger than the sum of its proper divisors (12950337).

28320399 is a wasteful number, since it uses less digits than its factorization.

28320399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27966 (or 27963 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 36.

The square root of 28320399 is about 5321.6913664736. The cubic root of 28320399 is about 304.8127454009.

The spelling of 28320399 in words is "twenty-eight million, three hundred twenty thousand, three hundred ninety-nine".