665165 has 4 divisors (see below), whose sum is σ = 798204. Its totient is φ = 532128.

The previous prime is 665153. The next prime is 665177. The reversal of 665165 is 561566.

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

It is an interprime number because it is at equal distance from previous prime (665153) and next prime (665177).

It can be written as a sum of positive squares in 2 ways, for example, as 90601 + 574564 = 301^2 + 758^2 .

It is a cyclic number.

It is not a de Polignac number, because 665165 - 2¹⁰ = 664141 is a prime.

It is a Duffinian number.

It is a plaindrome in base 14.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66512 + ... + 66521.

It is an arithmetic number, because the mean of its divisors is an integer number (199551).

2⁶⁶⁵¹⁶⁵ is an apocalyptic number.

It is an amenable number.

665165 is a deficient number, since it is larger than the sum of its proper divisors (133039).

665165 is a wasteful number, since it uses less digits than its factorization.

665165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133038.

The product of its digits is 5400, while the sum is 29.

The square root of 665165 is about 815.5764832313. The cubic root of 665165 is about 87.2924058305.

The spelling of 665165 in words is "six hundred sixty-five thousand, one hundred sixty-five".