28163231 has 4 divisors (see below), whose sum is σ = 28252392. Its totient is φ = 28074072.

The previous prime is 28163197. The next prime is 28163243. The reversal of 28163231 is 13236182.

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 28163231 - 2¹⁰ = 28162207 is a prime.

It is a super-2 number, since 2×28163231² = 1586335160718722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28163231.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28163731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44105 + ... + 44738.

It is an arithmetic number, because the mean of its divisors is an integer number (7063098).

Almost surely, 2^28163231 is an apocalyptic number.

28163231 is a deficient number, since it is larger than the sum of its proper divisors (89161).

28163231 is an equidigital number, since it uses as much as digits as its factorization.

28163231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89160.

The product of its digits is 1728, while the sum is 26.

The square root of 28163231 is about 5306.9040880724. The cubic root of 28163231 is about 304.2478321540.

The spelling of 28163231 in words is "twenty-eight million, one hundred sixty-three thousand, two hundred thirty-one".