28291 has 4 divisors (see below), whose sum is σ = 29800. Its totient is φ = 26784.

The previous prime is 28289. The next prime is 28297. The reversal of 28291 is 19282.

28291 = T₁₈ + T₁₉ + ... + T₅₅.

28291 is nontrivially palindromic in base 9.

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 28291 - 2¹ = 28289 is a prime.

It is a Duffinian number.

It is a plaindrome in base 12.

It is a nialpdrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28297) 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, 726 + ... + 763.

It is an arithmetic number, because the mean of its divisors is an integer number (7450).

2²⁸²⁹¹ is an apocalyptic number.

28291 is a deficient number, since it is larger than the sum of its proper divisors (1509).

28291 is a wasteful number, since it uses less digits than its factorization.

28291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1508.

The product of its digits is 288, while the sum is 22.

The square root of 28291 is about 168.1992865621. The cubic root of 28291 is about 30.4707234970.

Subtracting from 28291 its reverse (19282), we obtain a palindrome (9009).

It can be divided in two parts, 282 and 91, that added together give a palindrome (373).

The spelling of 28291 in words is "twenty-eight thousand, two hundred ninety-one".