8523209 has 4 divisors (see below), whose sum is σ = 8753604. Its totient is φ = 8292816.

The previous prime is 8523173. The next prime is 8523211. The reversal of 8523209 is 9023258.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9023258 = 2 ⋅4511629.

It can be written as a sum of positive squares in 2 ways, for example, as 5953600 + 2569609 = 2440^2 + 1603^2 .

It is a cyclic number.

It is not a de Polignac number, because 8523209 - 2²⁰ = 7474633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8523259) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 115142 + ... + 115215.

It is an arithmetic number, because the mean of its divisors is an integer number (2188401).

Almost surely, 2^8523209 is an apocalyptic number.

It is an amenable number.

8523209 is a deficient number, since it is larger than the sum of its proper divisors (230395).

8523209 is a wasteful number, since it uses less digits than its factorization.

8523209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230394.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 8523209 is about 2919.4535447580. The cubic root of 8523209 is about 204.2683336128.

The spelling of 8523209 in words is "eight million, five hundred twenty-three thousand, two hundred nine".