28000 has 48 divisors (see below), whose sum is σ = 78624. Its totient is φ = 9600.

The previous prime is 27997. The next prime is 28001. The reversal of 28000 is 82.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is a plaindrome in base 6.

It is a nialpdrome in base 8.

It is a zygodrome in base 6.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3997 + ... + 4003.

It is an arithmetic number, because the mean of its divisors is an integer number (1638).

2²⁸⁰⁰⁰ is an apocalyptic number.

28000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39312).

28000 is an abundant number, since it is smaller than the sum of its proper divisors (50624).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28000 is an equidigital number, since it uses as much as digits as its factorization.

28000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32 (or 14 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 28000 is about 167.3320053068. The cubic root of 28000 is about 30.3658897188.

Adding to 28000 its reverse (82), we get a palindrome (28082).

The spelling of 28000 in words is "twenty-eight thousand".