664866009 has 8 divisors (see below), whose sum is σ = 984986720. Its totient is φ = 443243988.

The previous prime is 664865947. The next prime is 664866017. The reversal of 664866009 is 900668466.

It is not a de Polignac number, because 664866009 - 2¹¹ = 664863961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (664866019) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12312307 + ... + 12312360.

It is an arithmetic number, because the mean of its divisors is an integer number (123123340).

Almost surely, 2^664866009 is an apocalyptic number.

It is an amenable number.

664866009 is a deficient number, since it is larger than the sum of its proper divisors (320120711).

664866009 is a wasteful number, since it uses less digits than its factorization.

664866009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24624676 (or 24624670 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 45.

The square root of 664866009 is about 25784.9958115180. The cubic root of 664866009 is about 872.7932458738.

The spelling of 664866009 in words is "six hundred sixty-four million, eight hundred sixty-six thousand, nine".