665657668 has 24 divisors (see below), whose sum is σ = 1294979840. Its totient is φ = 297315360.

The previous prime is 665657633. The next prime is 665657689. The reversal of 665657668 is 866756566.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 204858 + ... + 208081.

Almost surely, 2^665657668 is an apocalyptic number.

It is an amenable number.

665657668 is a deficient number, since it is larger than the sum of its proper divisors (629322172).

665657668 is a wasteful number, since it uses less digits than its factorization.

665657668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 412987 (or 412985 counting only the distinct ones).

The product of its digits is 10886400, while the sum is 55.

The square root of 665657668 is about 25800.3424008287. The cubic root of 665657668 is about 873.1395214438.

The spelling of 665657668 in words is "six hundred sixty-five million, six hundred fifty-seven thousand, six hundred sixty-eight".