28340 has 24 divisors (see below), whose sum is σ = 64680. Its totient is φ = 10368.

The previous prime is 28319. The next prime is 28349. The reversal of 28340 is 4382.

It can be written as a sum of positive squares in 4 ways, for example, as 1444 + 26896 = 38^2 + 164^2 .

It is a nialpdrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28349) by changing a digit.

28340 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 206 + ... + 314.

It is an arithmetic number, because the mean of its divisors is an integer number (2695).

2²⁸³⁴⁰ is an apocalyptic number.

28340 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 28340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32340).

28340 is an abundant number, since it is smaller than the sum of its proper divisors (36340).

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

28340 is a wasteful number, since it uses less digits than its factorization.

28340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131 (or 129 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 28340 is about 168.3448840922. The cubic root of 28340 is about 30.4883051105.

It can be divided in two parts, 283 and 40, that added together give a palindrome (323).

The spelling of 28340 in words is "twenty-eight thousand, three hundred forty".