665969978089 has 32 divisors (see below), whose sum is σ = 760795750400. Its totient is φ = 578487744000.

The previous prime is 665969978083. The next prime is 665969978153. The reversal of 665969978089 is 980879969566.

It is a cyclic number.

It is not a de Polignac number, because 665969978089 - 2⁷ = 665969977961 is a prime.

It is not an unprimeable number, because it can be changed into a prime (665969978083) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 26842312 + ... + 26867110.

It is an arithmetic number, because the mean of its divisors is an integer number (23774867200).

Almost surely, 2^665969978089 is an apocalyptic number.

It is an amenable number.

665969978089 is a deficient number, since it is larger than the sum of its proper divisors (94825772311).

665969978089 is a wasteful number, since it uses less digits than its factorization.

665969978089 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26681.

The product of its (nonzero) digits is 3174474240, while the sum is 82.

The spelling of 665969978089 in words is "six hundred sixty-five billion, nine hundred sixty-nine million, nine hundred seventy-eight thousand, eighty-nine".