28305 has 24 divisors (see below), whose sum is σ = 53352. Its totient is φ = 13824.

The previous prime is 28297. The next prime is 28307. The reversal of 28305 is 50382.

28305 = T₄₉ + T₅₀ + ... + T₆₅.

It can be written as a sum of positive squares in 4 ways, for example, as 11664 + 16641 = 108^2 + 129^2 .

It is not a de Polignac number, because 28305 - 2³ = 28297 is a prime.

It is a Curzon number.

It is a plaindrome in base 12.

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 (28307) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 747 + ... + 783.

It is an arithmetic number, because the mean of its divisors is an integer number (2223).

2²⁸³⁰⁵ is an apocalyptic number.

It is an amenable number.

28305 is a deficient number, since it is larger than the sum of its proper divisors (25047).

28305 is a wasteful number, since it uses less digits than its factorization.

28305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65 (or 62 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 28305 is about 168.2408987137. The cubic root of 28305 is about 30.4757488853.

Adding to 28305 its reverse (50382), we get a palindrome (78687).

It can be divided in two parts, 28 and 305, that added together give a palindrome (333).

The spelling of 28305 in words is "twenty-eight thousand, three hundred five".