28135809 has 32 divisors (see below), whose sum is σ = 45561600. Its totient is φ = 17055360.

The previous prime is 28135781. The next prime is 28135847. The reversal of 28135809 is 90853182.

It is not a de Polignac number, because 28135809 - 2⁵ = 28135777 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28135309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 24357 + ... + 25485.

It is an arithmetic number, because the mean of its divisors is an integer number (1423800).

Almost surely, 2^28135809 is an apocalyptic number.

It is an amenable number.

28135809 is a deficient number, since it is larger than the sum of its proper divisors (17425791).

28135809 is a wasteful number, since it uses less digits than its factorization.

28135809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1222 (or 1216 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The square root of 28135809 is about 5304.3198432975. The cubic root of 28135809 is about 304.1490533201.

The spelling of 28135809 in words is "twenty-eight million, one hundred thirty-five thousand, eight hundred nine".