28185231 has 16 divisors (see below), whose sum is σ = 39845888. Its totient is φ = 17690400.

The previous prime is 28185211. The next prime is 28185239. The reversal of 28185231 is 13258182.

It is not a de Polignac number, because 28185231 - 2⁷ = 28185103 is a prime.

It is a super-2 number, since 2×28185231² = 1588814493046722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28185239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 655 + ... + 7536.

It is an arithmetic number, because the mean of its divisors is an integer number (2490368).

Almost surely, 2^28185231 is an apocalyptic number.

28185231 is a deficient number, since it is larger than the sum of its proper divisors (11660657).

28185231 is a wasteful number, since it uses less digits than its factorization.

28185231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8262.

The product of its digits is 3840, while the sum is 30.

The square root of 28185231 is about 5308.9764550241. The cubic root of 28185231 is about 304.3270336511.

The spelling of 28185231 in words is "twenty-eight million, one hundred eighty-five thousand, two hundred thirty-one".