665173 has 4 divisors (see below), whose sum is σ = 688140. Its totient is φ = 642208.

The previous prime is 665153. The next prime is 665177. The reversal of 665173 is 371566.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 253009 + 412164 = 503^2 + 642^2 .

It is a cyclic number.

It is not a de Polignac number, because 665173 - 2⁵ = 665141 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665177) 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, 11440 + ... + 11497.

It is an arithmetic number, because the mean of its divisors is an integer number (172035).

2⁶⁶⁵¹⁷³ is an apocalyptic number.

It is an amenable number.

665173 is a deficient number, since it is larger than the sum of its proper divisors (22967).

665173 is a wasteful number, since it uses less digits than its factorization.

665173 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22966.

The product of its digits is 3780, while the sum is 28.

The square root of 665173 is about 815.5813877229. The cubic root of 665173 is about 87.2927557870.

It can be divided in two parts, 6651 and 73, that added together give a square (6724 = 82²).

The spelling of 665173 in words is "six hundred sixty-five thousand, one hundred seventy-three".