28549009 has 4 divisors (see below), whose sum is σ = 28615680. Its totient is φ = 28482340.

The previous prime is 28548977. The next prime is 28549013. The reversal of 28549009 is 90094582.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28549009 - 2⁵ = 28548977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28549309) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32689 + ... + 33550.

It is an arithmetic number, because the mean of its divisors is an integer number (7153920).

Almost surely, 2^28549009 is an apocalyptic number.

It is an amenable number.

28549009 is a deficient number, since it is larger than the sum of its proper divisors (66671).

28549009 is an equidigital number, since it uses as much as digits as its factorization.

28549009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66670.

The product of its (nonzero) digits is 25920, while the sum is 37.

The square root of 28549009 is about 5343.1272678086. The cubic root of 28549009 is about 305.6307256062.

It can be divided in two parts, 285 and 49009, that added together give a palindrome (49294).

The spelling of 28549009 in words is "twenty-eight million, five hundred forty-nine thousand, nine".