28186809 has 12 divisors (see below), whose sum is σ = 43718544. Its totient is φ = 16106664.

The previous prime is 28186783. The next prime is 28186813. The reversal of 28186809 is 90868182.

It is not a de Polignac number, because 28186809 - 2¹⁹ = 27662521 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28186849) 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 11 ways as a sum of consecutive naturals, for example, 95727 + ... + 96020.

It is an arithmetic number, because the mean of its divisors is an integer number (3643212).

Almost surely, 2^28186809 is an apocalyptic number.

It is an amenable number.

28186809 is a deficient number, since it is larger than the sum of its proper divisors (15531735).

28186809 is a wasteful number, since it uses less digits than its factorization.

28186809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191764 (or 191757 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 42.

The square root of 28186809 is about 5309.1250691616. The cubic root of 28186809 is about 304.3327129742.

The spelling of 28186809 in words is "twenty-eight million, one hundred eighty-six thousand, eight hundred nine".