28861 has 12 divisors (see below), whose sum is σ = 36480. Its totient is φ = 22680.

The previous prime is 28859. The next prime is 28867. The reversal of 28861 is 16882.

It is not a de Polignac number, because 28861 - 2¹ = 28859 is a prime.

Its product of digits (768) is a multiple of the sum of its prime factors (64).

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 (28867) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 916 + ... + 946.

It is an arithmetic number, because the mean of its divisors is an integer number (3040).

2²⁸⁸⁶¹ is an apocalyptic number.

It is an amenable number.

28861 is a deficient number, since it is larger than the sum of its proper divisors (7619).

28861 is a wasteful number, since it uses less digits than its factorization.

28861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64 (or 57 counting only the distinct ones).

The product of its digits is 768, while the sum is 25.

The square root of 28861 is about 169.8852553932. The cubic root of 28861 is about 30.6740031807.

The spelling of 28861 in words is "twenty-eight thousand, eight hundred sixty-one".