666605651609 has 16 divisors (see below), whose sum is σ = 670589285184. Its totient is φ = 662636184000.

The previous prime is 666605651521. The next prime is 666605651611. The reversal of 666605651609 is 906156506666.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666605651609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666605651629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 312812474 + ... + 312814604.

It is an arithmetic number, because the mean of its divisors is an integer number (41911830324).

Almost surely, 2^666605651609 is an apocalyptic number.

It is an amenable number.

666605651609 is a deficient number, since it is larger than the sum of its proper divisors (3983633575).

666605651609 is a wasteful number, since it uses less digits than its factorization.

666605651609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4648.

The product of its (nonzero) digits is 10497600, while the sum is 56.

The spelling of 666605651609 in words is "six hundred sixty-six billion, six hundred five million, six hundred fifty-one thousand, six hundred nine".