28168891 has 2 divisors, whose sum is σ = 28168892. Its totient is φ = 28168890.

The previous prime is 28168883. The next prime is 28168909. The reversal of 28168891 is 19886182.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28168891 - 2³ = 28168883 is a prime.

It is not a weakly prime, because it can be changed into another prime (28168841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14084445 + 14084446.

It is an arithmetic number, because the mean of its divisors is an integer number (14084446).

Almost surely, 2^28168891 is an apocalyptic number.

28168891 is a deficient number, since it is larger than the sum of its proper divisors (1).

28168891 is an equidigital number, since it uses as much as digits as its factorization.

28168891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 55296, while the sum is 43.

The square root of 28168891 is about 5307.4373288810. The cubic root of 28168891 is about 304.2682124788.

The spelling of 28168891 in words is "twenty-eight million, one hundred sixty-eight thousand, eight hundred ninety-one".