28400 has 30 divisors (see below), whose sum is σ = 69192. Its totient is φ = 11200.

The previous prime is 28393. The next prime is 28403. The reversal of 28400 is 482.

28400 is nontrivially palindromic in base 7.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28403) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 365 + ... + 435.

2²⁸⁴⁰⁰ is an apocalyptic number.

28400 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 28400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34596).

28400 is an abundant number, since it is smaller than the sum of its proper divisors (40792).

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

28400 is a wasteful number, since it uses less digits than its factorization.

28400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89 (or 78 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 28400 is about 168.5229954635. The cubic root of 28400 is about 30.5098060380.

Adding to 28400 its reverse (482), we get a palindrome (28882).

The spelling of 28400 in words is "twenty-eight thousand, four hundred".