8549173666609 has 3 divisors (see below), whose sum is σ = 8549176590507. Its totient is φ = 8549170742712.

The previous prime is 8549173666589. The next prime is 8549173666741. The reversal of 8549173666609 is 9066663719458.

The square root of 8549173666609 is 2923897.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 7257932343025 + 1291241323584 = 2694055^2 + 1136328^2 .

It is not a de Polignac number, because 8549173666609 - 2¹⁵ = 8549173633841 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8549173666009) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 1461949 + ... + 4385845.

It is an arithmetic number, because the mean of its divisors is an integer number (2849725530169).

Almost surely, 2^{8549173666609} is an apocalyptic number.

8549173666609 is the 2923897-th square number.

8549173666609 is the 1461949-th centered octagonal number.

It is an amenable number.

8549173666609 is a deficient number, since it is larger than the sum of its proper divisors (2923898).

8549173666609 is an frugal number, since it uses more digits than its factorization.

8549173666609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5847794 (or 2923897 counting only the distinct ones).

The product of its (nonzero) digits is 352719360, while the sum is 70.

The spelling of 8549173666609 in words is "eight trillion, five hundred forty-nine billion, one hundred seventy-three million, six hundred sixty-six thousand, six hundred nine".