28891 has 4 divisors (see below), whose sum is σ = 29232. Its totient is φ = 28552.

The previous prime is 28879. The next prime is 28901. The reversal of 28891 is 19882.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 19882 = 2 ⋅9941.

It is a cyclic number.

It is not a de Polignac number, because 28891 - 2⁵ = 28859 is a prime.

It is a Duffinian number.

28891 is a lucky number.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28871) 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, 81 + ... + 253.

It is an arithmetic number, because the mean of its divisors is an integer number (7308).

2²⁸⁸⁹¹ is an apocalyptic number.

28891 is the 108-th centered pentagonal number.

28891 is a deficient number, since it is larger than the sum of its proper divisors (341).

28891 is a wasteful number, since it uses less digits than its factorization.

28891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 340.

The product of its digits is 1152, while the sum is 28.

The square root of 28891 is about 169.9735273506. The cubic root of 28891 is about 30.6846276847.

Subtracting from 28891 its reverse (19882), we obtain a palindrome (9009).

It can be divided in two parts, 28 and 891, that added together give a palindrome (919).

The spelling of 28891 in words is "twenty-eight thousand, eight hundred ninety-one".