28389909 has 4 divisors (see below), whose sum is σ = 37853216. Its totient is φ = 18926604.

The previous prime is 28389887. The next prime is 28389923. The reversal of 28389909 is 90998382.

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 not a de Polignac number, because 28389909 - 2⁵ = 28389877 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28389929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4731649 + ... + 4731654.

It is an arithmetic number, because the mean of its divisors is an integer number (9463304).

Almost surely, 2^28389909 is an apocalyptic number.

It is an amenable number.

28389909 is a deficient number, since it is larger than the sum of its proper divisors (9463307).

28389909 is an equidigital number, since it uses as much as digits as its factorization.

28389909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9463306.

The product of its (nonzero) digits is 279936, while the sum is 48.

The square root of 28389909 is about 5328.2181824696. The cubic root of 28389909 is about 305.0619206002.

The spelling of 28389909 in words is "twenty-eight million, three hundred eighty-nine thousand, nine hundred nine".