28389 has 4 divisors (see below), whose sum is σ = 37856. Its totient is φ = 18924.

The previous prime is 28387. The next prime is 28393. The reversal of 28389 is 98382.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 28389 - 2¹ = 28387 is a prime.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28387) 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, 4729 + ... + 4734.

It is an arithmetic number, because the mean of its divisors is an integer number (9464).

2²⁸³⁸⁹ is an apocalyptic number.

It is an amenable number.

28389 is a deficient number, since it is larger than the sum of its proper divisors (9467).

28389 is an equidigital number, since it uses as much as digits as its factorization.

28389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9466.

The product of its digits is 3456, while the sum is 30.

The square root of 28389 is about 168.4903558071. The cubic root of 28389 is about 30.5058664699.

The spelling of 28389 in words is "twenty-eight thousand, three hundred eighty-nine".