28368391 has 4 divisors (see below), whose sum is σ = 28432872. Its totient is φ = 28303912.

The previous prime is 28368343. The next prime is 28368419. The reversal of 28368391 is 19386382.

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 28368391 - 2¹¹ = 28366343 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 (28368341) 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 3 ways as a sum of consecutive naturals, for example, 31576 + ... + 32461.

It is an arithmetic number, because the mean of its divisors is an integer number (7108218).

Almost surely, 2^28368391 is an apocalyptic number.

28368391 is a deficient number, since it is larger than the sum of its proper divisors (64481).

28368391 is an equidigital number, since it uses as much as digits as its factorization.

28368391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64480.

The product of its digits is 62208, while the sum is 40.

The square root of 28368391 is about 5326.1985505612. The cubic root of 28368391 is about 304.9848276964.

Subtracting from 28368391 its reverse (19386382), we obtain a square (8982009 = 2997²).

The spelling of 28368391 in words is "twenty-eight million, three hundred sixty-eight thousand, three hundred ninety-one".