666309789 has 12 divisors (see below), whose sum is σ = 963142336. Its totient is φ = 443885832.

The previous prime is 666309733. The next prime is 666309797. The reversal of 666309789 is 987903666.

It is a happy number.

It is not a de Polignac number, because 666309789 - 2²⁴ = 649532573 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 (666309719) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13207 + ... + 38820.

Almost surely, 2^666309789 is an apocalyptic number.

It is an amenable number.

666309789 is a deficient number, since it is larger than the sum of its proper divisors (296832547).

666309789 is a wasteful number, since it uses less digits than its factorization.

666309789 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53456 (or 53453 counting only the distinct ones).

The product of its (nonzero) digits is 2939328, while the sum is 54.

The square root of 666309789 is about 25812.9771432898. The cubic root of 666309789 is about 873.4245562339.

The spelling of 666309789 in words is "six hundred sixty-six million, three hundred nine thousand, seven hundred eighty-nine".