85728209 has 16 divisors (see below), whose sum is σ = 103459200. Its totient is φ = 69393024.

The previous prime is 85728187. The next prime is 85728217. The reversal of 85728209 is 90282758.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 85728209 - 2¹⁶ = 85662673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (85728259) 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 15 ways as a sum of consecutive naturals, for example, 50909 + ... + 52565.

It is an arithmetic number, because the mean of its divisors is an integer number (6466200).

Almost surely, 2^85728209 is an apocalyptic number.

It is an amenable number.

85728209 is a deficient number, since it is larger than the sum of its proper divisors (17730991).

85728209 is a wasteful number, since it uses less digits than its factorization.

85728209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2072.

The product of its (nonzero) digits is 80640, while the sum is 41.

The square root of 85728209 is about 9258.9529105618. The cubic root of 85728209 is about 440.9350106393.

The spelling of 85728209 in words is "eighty-five million, seven hundred twenty-eight thousand, two hundred nine".