28805 has 8 divisors (see below), whose sum is σ = 39552. Its totient is φ = 19728.

The previous prime is 28793. The next prime is 28807. The reversal of 28805 is 50882.

28805 = T₁₄ + T₁₅ + ... + T₅₅.

28805 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28805 - 2⁴ = 28789 is a prime.

It is a Duffinian number.

28805 is strictly pandigital in base 6.

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 28805.

It is not an unprimeable number, because it can be changed into a prime (28807) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 377 + ... + 446.

It is an arithmetic number, because the mean of its divisors is an integer number (4944).

2²⁸⁸⁰⁵ is an apocalyptic number.

It is an amenable number.

28805 is a deficient number, since it is larger than the sum of its proper divisors (10747).

28805 is an equidigital number, since it uses as much as digits as its factorization.

28805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 835.

The product of its (nonzero) digits is 640, while the sum is 23.

The square root of 28805 is about 169.7203582367. The cubic root of 28805 is about 30.6541510575.

Subtracting from 28805 its sum of digits (23), we obtain a palindrome (28782).

It can be divided in two parts, 2880 and 5, that multiplied together give a square (14400 = 120²).

The spelling of 28805 in words is "twenty-eight thousand, eight hundred five".