28167391 has 4 divisors (see below), whose sum is σ = 32191312. Its totient is φ = 24143472.

The previous prime is 28167383. The next prime is 28167427. The reversal of 28167391 is 19376182.

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 28167391 - 2³ = 28167383 is a prime.

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 28167391.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28167301) 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, 2011950 + ... + 2011963.

It is an arithmetic number, because the mean of its divisors is an integer number (8047828).

Almost surely, 2^28167391 is an apocalyptic number.

28167391 is a deficient number, since it is larger than the sum of its proper divisors (4023921).

28167391 is an equidigital number, since it uses as much as digits as its factorization.

28167391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4023920.

The product of its digits is 18144, while the sum is 37.

The square root of 28167391 is about 5307.2960158634. The cubic root of 28167391 is about 304.2628115985.

The spelling of 28167391 in words is "twenty-eight million, one hundred sixty-seven thousand, three hundred ninety-one".