28815 has 16 divisors (see below), whose sum is σ = 49248. Its totient is φ = 14336.

The previous prime is 28813. The next prime is 28817. The reversal of 28815 is 51882.

It is an interprime number because it is at equal distance from previous prime (28813) and next prime (28817).

It is a cyclic number.

It is not a de Polignac number, because 28815 - 2¹ = 28813 is a prime.

28815 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 (28813) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 199 + ... + 311.

It is an arithmetic number, because the mean of its divisors is an integer number (3078).

2²⁸⁸¹⁵ is an apocalyptic number.

28815 is a deficient number, since it is larger than the sum of its proper divisors (20433).

28815 is a wasteful number, since it uses less digits than its factorization.

28815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138.

The product of its digits is 640, while the sum is 24.

The square root of 28815 is about 169.7498159056. The cubic root of 28815 is about 30.6576979654.

It can be divided in two parts, 288 and 15, that added together give a palindrome (303).

The spelling of 28815 in words is "twenty-eight thousand, eight hundred fifteen".