28304389 has 4 divisors (see below), whose sum is σ = 28569024. Its totient is φ = 28039756.

The previous prime is 28304347. The next prime is 28304399. The reversal of 28304389 is 98340382.

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 a de Polignac number, because none of the positive numbers 2^k-28304389 is a prime.

It is a super-2 number, since 2×28304389² = 1602276873326642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28304399) 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, 132157 + ... + 132370.

It is an arithmetic number, because the mean of its divisors is an integer number (7142256).

Almost surely, 2^28304389 is an apocalyptic number.

It is an amenable number.

28304389 is a deficient number, since it is larger than the sum of its proper divisors (264635).

28304389 is a wasteful number, since it uses less digits than its factorization.

28304389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 264634.

The product of its (nonzero) digits is 41472, while the sum is 37.

The square root of 28304389 is about 5320.1869328060. The cubic root of 28304389 is about 304.7552959756.

The spelling of 28304389 in words is "twenty-eight million, three hundred four thousand, three hundred eighty-nine".