28775 has 6 divisors (see below), whose sum is σ = 35712. Its totient is φ = 23000.

The previous prime is 28771. The next prime is 28789. The reversal of 28775 is 57782.

It is not a de Polignac number, because 28775 - 2² = 28771 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a plaindrome in base 12.

It is a zygodrome in base 2.

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 28775.

It is not an unprimeable number, because it can be changed into a prime (28771) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 551 + ... + 600.

It is an arithmetic number, because the mean of its divisors is an integer number (5952).

2²⁸⁷⁷⁵ is an apocalyptic number.

28775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

28775 is a deficient number, since it is larger than the sum of its proper divisors (6937).

28775 is a wasteful number, since it uses less digits than its factorization.

28775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1161 (or 1156 counting only the distinct ones).

The product of its digits is 3920, while the sum is 29.

The square root of 28775 is about 169.6319545369. The cubic root of 28775 is about 30.6435054060.

It can be divided in two parts, 2877 and 5, that added together give a palindrome (2882).

The spelling of 28775 in words is "twenty-eight thousand, seven hundred seventy-five".