666605509949 has 8 divisors (see below), whose sum is σ = 671732455680. Its totient is φ = 661479145600.

The previous prime is 666605509939. The next prime is 666605509961. The reversal of 666605509949 is 949905506666.

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 666605509949 - 2⁸ = 666605509693 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 (666605509939) 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, 2316269 + ... + 2588109.

It is an arithmetic number, because the mean of its divisors is an integer number (83966556960).

Almost surely, 2^666605509949 is an apocalyptic number.

It is an amenable number.

666605509949 is a deficient number, since it is larger than the sum of its proper divisors (5126945731).

666605509949 is a wasteful number, since it uses less digits than its factorization.

666605509949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 290691.

The product of its (nonzero) digits is 94478400, while the sum is 65.

The spelling of 666605509949 in words is "six hundred sixty-six billion, six hundred five million, five hundred nine thousand, nine hundred forty-nine".