28391209809 has 16 divisors (see below), whose sum is σ = 38523992640. Its totient is φ = 18593732160.

The previous prime is 28391209789. The next prime is 28391209817. The reversal of 28391209809 is 90890219382.

It is not a de Polignac number, because 28391209809 - 2²⁷ = 28256992081 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28391209009) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 48522 + ... + 243180.

It is an arithmetic number, because the mean of its divisors is an integer number (2407749540).

Almost surely, 2^28391209809 is an apocalyptic number.

It is an amenable number.

28391209809 is a deficient number, since it is larger than the sum of its proper divisors (10132782831).

28391209809 is a wasteful number, since it uses less digits than its factorization.

28391209809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195520.

The product of its (nonzero) digits is 559872, while the sum is 51.

The spelling of 28391209809 in words is "twenty-eight billion, three hundred ninety-one million, two hundred nine thousand, eight hundred nine".