28131 has 4 divisors (see below), whose sum is σ = 37512. Its totient is φ = 18752.

The previous prime is 28123. The next prime is 28151. The reversal of 28131 is 13182.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28131 - 2³ = 28123 is a prime.

It is a super-2 number, since 2×28131² = 1582706322, which contains 22 as substring.

It is a D-number.

28131 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 28131.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 28131.

It is not an unprimeable number, because it can be changed into a prime (28111) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4686 + ... + 4691.

It is an arithmetic number, because the mean of its divisors is an integer number (9378).

2²⁸¹³¹ is an apocalyptic number.

28131 is a deficient number, since it is larger than the sum of its proper divisors (9381).

28131 is an equidigital number, since it uses as much as digits as its factorization.

28131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9380.

The product of its digits is 48, while the sum is 15.

The square root of 28131 is about 167.7229859024. The cubic root of 28131 is about 30.4131723848.

The spelling of 28131 in words is "twenty-eight thousand, one hundred thirty-one".