28115 has 4 divisors (see below), whose sum is σ = 33744. Its totient is φ = 22488.

The previous prime is 28111. The next prime is 28123. The reversal of 28115 is 51182.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28115 - 2² = 28111 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28093 and 28102.

It is not an unprimeable number, because it can be changed into a prime (28111) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2807 + ... + 2816.

It is an arithmetic number, because the mean of its divisors is an integer number (8436).

2²⁸¹¹⁵ is an apocalyptic number.

28115 is a deficient number, since it is larger than the sum of its proper divisors (5629).

28115 is an equidigital number, since it uses as much as digits as its factorization.

28115 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5628.

The product of its digits is 80, while the sum is 17.

The square root of 28115 is about 167.6752814222. The cubic root of 28115 is about 30.4074052828.

Adding to 28115 its reverse (51182), we get a palindrome (79297).

The spelling of 28115 in words is "twenty-eight thousand, one hundred fifteen".