28065091 has 4 divisors (see below), whose sum is σ = 28138752. Its totient is φ = 27991432.

The previous prime is 28065077. The next prime is 28065101. The reversal of 28065091 is 19056082.

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 28065091 - 2⁷ = 28064963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28065041) 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, 36256 + ... + 37021.

It is an arithmetic number, because the mean of its divisors is an integer number (7034688).

Almost surely, 2^28065091 is an apocalyptic number.

28065091 is a deficient number, since it is larger than the sum of its proper divisors (73661).

28065091 is an equidigital number, since it uses as much as digits as its factorization.

28065091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73660.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 28065091 is about 5297.6495731598. The cubic root of 28065091 is about 303.8940181984.

Subtracting from 28065091 its reverse (19056082), we obtain a palindrome (9009009).

The spelling of 28065091 in words is "twenty-eight million, sixty-five thousand, ninety-one".