666909667 has 8 divisors (see below), whose sum is σ = 669260880. Its totient is φ = 664563840.

The previous prime is 666909641. The next prime is 666909673. The reversal of 666909667 is 766909666.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 666909667 - 2⁷ = 666909539 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666909967) 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, 558423 + ... + 559615.

It is an arithmetic number, because the mean of its divisors is an integer number (83657610).

Almost surely, 2^666909667 is an apocalyptic number.

666909667 is a deficient number, since it is larger than the sum of its proper divisors (2351213).

666909667 is a wasteful number, since it uses less digits than its factorization.

666909667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2693.

The product of its (nonzero) digits is 4408992, while the sum is 55.

The square root of 666909667 is about 25824.5942272091. The cubic root of 666909667 is about 873.6865920149.

Subtracting 666909667 from its reverse (766909666), we obtain a palindrome (99999999).

The spelling of 666909667 in words is "six hundred sixty-six million, nine hundred nine thousand, six hundred sixty-seven".