28168191 has 6 divisors (see below), whose sum is σ = 40687400. Its totient is φ = 18778788.

The previous prime is 28168187. The next prime is 28168199. The reversal of 28168191 is 19186182.

It is not a de Polignac number, because 28168191 - 2² = 28168187 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28168199) 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, 1564891 + ... + 1564908.

Almost surely, 2^28168191 is an apocalyptic number.

28168191 is a deficient number, since it is larger than the sum of its proper divisors (12519209).

28168191 is a wasteful number, since it uses less digits than its factorization.

28168191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3129805 (or 3129802 counting only the distinct ones).

The product of its digits is 6912, while the sum is 36.

The square root of 28168191 is about 5307.3713832744. The cubic root of 28168191 is about 304.2656920918.

Subtracting from 28168191 its reverse (19186182), we obtain a square (8982009 = 2997²).

The spelling of 28168191 in words is "twenty-eight million, one hundred sixty-eight thousand, one hundred ninety-one".