28305389 has 10 divisors (see below), whose sum is σ = 33023790. Its totient is φ = 24259704.

The previous prime is 28305371. The next prime is 28305397. The reversal of 28305389 is 98350382.

It can be written as a sum of positive squares in only one way, i.e., 16540489 + 11764900 = 4067^2 + 3430^2 .

It is not a de Polignac number, because 28305389 - 2⁸ = 28305133 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 (28305349) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 3494 + ... + 8295.

It is an arithmetic number, because the mean of its divisors is an integer number (3302379).

Almost surely, 2^28305389 is an apocalyptic number.

It is an amenable number.

28305389 is a deficient number, since it is larger than the sum of its proper divisors (4718401).

28305389 is an frugal number, since it uses more digits than its factorization.

28305389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11817 (or 11796 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 38.

The square root of 28305389 is about 5320.2809136360. The cubic root of 28305389 is about 304.7588849562.

The spelling of 28305389 in words is "twenty-eight million, three hundred five thousand, three hundred eighty-nine".