28105 has 16 divisors (see below), whose sum is σ = 42624. Its totient is φ = 17280.

The previous prime is 28099. The next prime is 28109. The reversal of 28105 is 50182.

It is a happy number.

It is not a de Polignac number, because 28105 - 2³ = 28097 is a prime.

It is a Duffinian number.

28105 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (28109) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 349 + ... + 421.

It is an arithmetic number, because the mean of its divisors is an integer number (2664).

2²⁸¹⁰⁵ is an apocalyptic number.

It is an amenable number.

28105 is a deficient number, since it is larger than the sum of its proper divisors (14519).

28105 is a wasteful number, since it uses less digits than its factorization.

28105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96.

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 28105 is about 167.6454592287. The cubic root of 28105 is about 30.4037997328.

Adding to 28105 its reverse (50182), we get a palindrome (78287).

The spelling of 28105 in words is "twenty-eight thousand, one hundred five".