28881 has 6 divisors (see below), whose sum is σ = 41730. Its totient is φ = 19248.

The previous prime is 28879. The next prime is 28901. The reversal of 28881 is 18882.

It can be written as a sum of positive squares in only one way, i.e., 25281 + 3600 = 159^2 + 60^2 .

It is not a de Polignac number, because 28881 - 2¹ = 28879 is a prime.

It is a super-2 number, since 2×28881² = 1668224322, which contains 22 as substring.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 28881.

It is not an unprimeable number, because it can be changed into a prime (28871) 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 5 ways as a sum of consecutive naturals, for example, 1596 + ... + 1613.

It is an arithmetic number, because the mean of its divisors is an integer number (6955).

2²⁸⁸⁸¹ is an apocalyptic number.

It is an amenable number.

28881 is a deficient number, since it is larger than the sum of its proper divisors (12849).

28881 is a wasteful number, since it uses less digits than its factorization.

28881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3215 (or 3212 counting only the distinct ones).

The product of its digits is 1024, while the sum is 27.

The square root of 28881 is about 169.9441084592. The cubic root of 28881 is about 30.6810870009.

Subtracting from 28881 its reverse (18882), we obtain a palindrome (9999).

It can be divided in two parts, 28 and 881, that added together give a palindrome (909).

The spelling of 28881 in words is "twenty-eight thousand, eight hundred eighty-one".