28399 has 4 divisors (see below), whose sum is σ = 32464. Its totient is φ = 24336.

The previous prime is 28393. The next prime is 28403. The reversal of 28399 is 99382.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28399 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a self number, because there is not a number n which added to its sum of digits gives 28399.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28393) 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, 2022 + ... + 2035.

It is an arithmetic number, because the mean of its divisors is an integer number (8116).

2²⁸³⁹⁹ is an apocalyptic number.

28399 is a deficient number, since it is larger than the sum of its proper divisors (4065).

28399 is an equidigital number, since it uses as much as digits as its factorization.

28399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4064.

The product of its digits is 3888, while the sum is 31.

The square root of 28399 is about 168.5200284833. The cubic root of 28399 is about 30.5094479375.

The spelling of 28399 in words is "twenty-eight thousand, three hundred ninety-nine".