28643209 has 8 divisors (see below), whose sum is σ = 32902848. Its totient is φ = 24425520.

The previous prime is 28643207. The next prime is 28643233. The reversal of 28643209 is 90234682.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 28643209 - 2¹ = 28643207 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28643201) 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 7 ways as a sum of consecutive naturals, for example, 9007 + ... + 11764.

It is an arithmetic number, because the mean of its divisors is an integer number (4112856).

Almost surely, 2^28643209 is an apocalyptic number.

It is an amenable number.

28643209 is a deficient number, since it is larger than the sum of its proper divisors (4259639).

28643209 is a wasteful number, since it uses less digits than its factorization.

28643209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20975.

The product of its (nonzero) digits is 20736, while the sum is 34.

The square root of 28643209 is about 5351.9350706076. The cubic root of 28643209 is about 305.9665085022.

The spelling of 28643209 in words is "twenty-eight million, six hundred forty-three thousand, two hundred nine".