664012165 has 4 divisors (see below), whose sum is σ = 796814604. Its totient is φ = 531209728.

The previous prime is 664012127. The next prime is 664012199. The reversal of 664012165 is 561210466.

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 73376356 + 590635809 = 8566^2 + 24303^2 .

It is a cyclic number.

It is not a de Polignac number, because 664012165 - 2¹⁵ = 663979397 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

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, 66401212 + ... + 66401221.

It is an arithmetic number, because the mean of its divisors is an integer number (199203651).

Almost surely, 2^664012165 is an apocalyptic number.

It is an amenable number.

664012165 is a deficient number, since it is larger than the sum of its proper divisors (132802439).

664012165 is a wasteful number, since it uses less digits than its factorization.

664012165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132802438.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 664012165 is about 25768.4334991478. The cubic root of 664012165 is about 872.4194620285.

The spelling of 664012165 in words is "six hundred sixty-four million, twelve thousand, one hundred sixty-five".