28109 has 2 divisors, whose sum is σ = 28110. Its totient is φ = 28108.

The previous prime is 28099. The next prime is 28111. The reversal of 28109 is 90182.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14884 + 13225 = 122^2 + 115^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28109 is a prime.

Together with 28111, it forms a pair of twin primes.

It is a Chen prime.

It is a nialpdrome in base 13.

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 28109.

It is not a weakly prime, because it can be changed into another prime (28309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14054 + 14055.

It is an arithmetic number, because the mean of its divisors is an integer number (14055).

2²⁸¹⁰⁹ is an apocalyptic number.

It is an amenable number.

28109 is a deficient number, since it is larger than the sum of its proper divisors (1).

28109 is an equidigital number, since it uses as much as digits as its factorization.

28109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 20.

The square root of 28109 is about 167.6573887426. The cubic root of 28109 is about 30.4052420554.

The spelling of 28109 in words is "twenty-eight thousand, one hundred nine".