666470209 has 4 divisors (see below), whose sum is σ = 687969280. Its totient is φ = 644971140.

The previous prime is 666470183. The next prime is 666470213. The reversal of 666470209 is 902074666.

666470209 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 666470209 - 2⁷ = 666470081 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666470249) 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, 10749489 + ... + 10749550.

It is an arithmetic number, because the mean of its divisors is an integer number (171992320).

Almost surely, 2^666470209 is an apocalyptic number.

It is an amenable number.

666470209 is a deficient number, since it is larger than the sum of its proper divisors (21499071).

666470209 is a wasteful number, since it uses less digits than its factorization.

666470209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21499070.

The product of its (nonzero) digits is 108864, while the sum is 40.

The square root of 666470209 is about 25816.0843080433. The cubic root of 666470209 is about 873.4946455160.

The spelling of 666470209 in words is "six hundred sixty-six million, four hundred seventy thousand, two hundred nine".