28445391 has 16 divisors (see below), whose sum is σ = 45383520. Its totient is φ = 17504640.

The previous prime is 28445371. The next prime is 28445401. The reversal of 28445391 is 19354482.

It is not a de Polignac number, because 28445391 - 2⁵ = 28445359 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28445311) 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 15 ways as a sum of consecutive naturals, for example, 40170 + ... + 40871.

It is an arithmetic number, because the mean of its divisors is an integer number (2836470).

Almost surely, 2^28445391 is an apocalyptic number.

28445391 is a deficient number, since it is larger than the sum of its proper divisors (16938129).

28445391 is a wasteful number, since it uses less digits than its factorization.

28445391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81063 (or 81057 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 28445391 is about 5333.4220721784. The cubic root of 28445391 is about 305.2605173588.

Subtracting from 28445391 its reverse (19354482), we obtain a palindrome (9090909).

The spelling of 28445391 in words is "twenty-eight million, four hundred forty-five thousand, three hundred ninety-one".