28665 has 36 divisors (see below), whose sum is σ = 62244. Its totient is φ = 12096.

The previous prime is 28663. The next prime is 28669. The reversal of 28665 is 56682.

28665 is nontrivially palindromic in base 4.

It can be written as a sum of positive squares in 2 ways, for example, as 7056 + 21609 = 84^2 + 147^2 .

It is not a de Polignac number, because 28665 - 2¹ = 28663 is a prime.

It is a Curzon number.

It is a nialpdrome in base 15.

It is a zygodrome in base 3.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 28665.

It is not an unprimeable number, because it can be changed into a prime (28661) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 2199 + ... + 2211.

It is an arithmetic number, because the mean of its divisors is an integer number (1729).

2²⁸⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

28665 is an abundant number, since it is smaller than the sum of its proper divisors (33579).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31122).

28665 is a wasteful number, since it uses less digits than its factorization.

28665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38 (or 28 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 28665 is about 169.3074127143. The cubic root of 28665 is about 30.6044079258.

It can be divided in two parts, 286 and 65, that added together give a triangular number (351 = T₂₆).

The spelling of 28665 in words is "twenty-eight thousand, six hundred sixty-five".