666392717 has 4 divisors (see below), whose sum is σ = 666656700. Its totient is φ = 666128736.

The previous prime is 666392689. The next prime is 666392759. The reversal of 666392717 is 717293666.

It is a happy number.

666392717 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 an emirpimes, since its reverse is a distinct semiprime: 717293666 = 2 ⋅358646833.

It can be written as a sum of positive squares in 2 ways, for example, as 291350761 + 375041956 = 17069^2 + 19366^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666392717 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666392767) 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, 128168 + ... + 133265.

It is an arithmetic number, because the mean of its divisors is an integer number (166664175).

Almost surely, 2^666392717 is an apocalyptic number.

It is an amenable number.

666392717 is a deficient number, since it is larger than the sum of its proper divisors (263983).

666392717 is a wasteful number, since it uses less digits than its factorization.

666392717 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 263982.

The product of its digits is 571536, while the sum is 47.

The square root of 666392717 is about 25814.5834171307. The cubic root of 666392717 is about 873.4607898038.

The spelling of 666392717 in words is "six hundred sixty-six million, three hundred ninety-two thousand, seven hundred seventeen".