664165 has 4 divisors (see below), whose sum is σ = 797004. Its totient is φ = 531328.

The previous prime is 664151. The next prime is 664177. The reversal of 664165 is 561466.

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 83521 + 580644 = 289^2 + 762^2 .

It is a cyclic number.

It is not a de Polignac number, because 664165 - 2⁵ = 664133 is a prime.

It is a super-2 number, since 2×664165² = 882230294450, which contains 22 as substring.

It is a Duffinian number.

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, 66412 + ... + 66421.

It is an arithmetic number, because the mean of its divisors is an integer number (199251).

2⁶⁶⁴¹⁶⁵ is an apocalyptic number.

It is an amenable number.

664165 is a deficient number, since it is larger than the sum of its proper divisors (132839).

664165 is a wasteful number, since it uses less digits than its factorization.

664165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132838.

The product of its digits is 4320, while the sum is 28.

The square root of 664165 is about 814.9631893527. The cubic root of 664165 is about 87.2486391525.

The spelling of 664165 in words is "six hundred sixty-four thousand, one hundred sixty-five".