28039 has 4 divisors (see below), whose sum is σ = 30600. Its totient is φ = 25480.

The previous prime is 28031. The next prime is 28051. The reversal of 28039 is 93082.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28039 - 2³ = 28031 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

28039 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28031) 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, 1264 + ... + 1285.

It is an arithmetic number, because the mean of its divisors is an integer number (7650).

2²⁸⁰³⁹ is an apocalyptic number.

28039 is a deficient number, since it is larger than the sum of its proper divisors (2561).

28039 is a wasteful number, since it uses less digits than its factorization.

28039 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2560.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 28039 is about 167.4484995454. The cubic root of 28039 is about 30.3799816269.

Adding to 28039 its reverse (93082), we get a palindrome (121121).

The spelling of 28039 in words is "twenty-eight thousand, thirty-nine".