28888309 has 4 divisors (see below), whose sum is σ = 29115904. Its totient is φ = 28660716.

The previous prime is 28888297. The next prime is 28888331. The reversal of 28888309 is 90388882.

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 28888309 - 2⁹ = 28887797 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 (28888369) 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, 113607 + ... + 113860.

It is an arithmetic number, because the mean of its divisors is an integer number (7278976).

Almost surely, 2^28888309 is an apocalyptic number.

It is an amenable number.

28888309 is a deficient number, since it is larger than the sum of its proper divisors (227595).

28888309 is a wasteful number, since it uses less digits than its factorization.

28888309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227594.

The product of its (nonzero) digits is 221184, while the sum is 46.

The square root of 28888309 is about 5374.7845538217. The cubic root of 28888309 is about 306.8367496705.

The spelling of 28888309 in words is "twenty-eight million, eight hundred eighty-eight thousand, three hundred nine".