28869 has 4 divisors (see below), whose sum is σ = 38496. Its totient is φ = 19244.

The previous prime is 28867. The next prime is 28871. The reversal of 28869 is 96882.

Added to its reverse (96882) it gives a triangular number (125751 = T₅₀₁).

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (28867) and next prime (28871).

It is a cyclic number.

It is not a de Polignac number, because 28869 - 2¹ = 28867 is a prime.

It is a super-2 number, since 2×28869² = 1666838322, which contains 22 as substring.

It is a D-number.

28869 is a lucky number.

It is a nialpdrome in base 14.

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 28869.

It is not an unprimeable number, because it can be changed into a prime (28867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4809 + ... + 4814.

It is an arithmetic number, because the mean of its divisors is an integer number (9624).

2²⁸⁸⁶⁹ is an apocalyptic number.

It is an amenable number.

28869 is a deficient number, since it is larger than the sum of its proper divisors (9627).

28869 is an equidigital number, since it uses as much as digits as its factorization.

28869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9626.

The product of its digits is 6912, while the sum is 33.

The square root of 28869 is about 169.9087990659. The cubic root of 28869 is about 30.6768371013.

Adding to 28869 its reverse (96882), we get a triangular number (125751 = T₅₀₁).

The spelling of 28869 in words is "twenty-eight thousand, eight hundred sixty-nine".