28511 has 4 divisors (see below), whose sum is σ = 32592. Its totient is φ = 24432.

The previous prime is 28499. The next prime is 28513. The reversal of 28511 is 11582.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11582 = 2 ⋅5791.

It is a cyclic number.

It is not a de Polignac number, because 28511 - 2⁶ = 28447 is a prime.

It is an Ulam number.

It is a plaindrome in base 6 and base 12.

It is a nialpdrome in base 13.

It is a zygodrome in base 3 and base 6.

It is a self number, because there is not a number n which added to its sum of digits gives 28511.

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 28511.

It is not an unprimeable number, because it can be changed into a prime (28513) 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, 2030 + ... + 2043.

It is an arithmetic number, because the mean of its divisors is an integer number (8148).

2²⁸⁵¹¹ is an apocalyptic number.

28511 is a deficient number, since it is larger than the sum of its proper divisors (4081).

28511 is an equidigital number, since it uses as much as digits as its factorization.

28511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4080.

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

The square root of 28511 is about 168.8520062066. The cubic root of 28511 is about 30.5495030559.

The spelling of 28511 in words is "twenty-eight thousand, five hundred eleven".