666563645 has 8 divisors (see below), whose sum is σ = 872592480. Its totient is φ = 484773520.

The previous prime is 666563641. The next prime is 666563687. The reversal of 666563645 is 546365666.

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

It is not a de Polignac number, because 666563645 - 2² = 666563641 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 666563645.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666563641) 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 7 ways as a sum of consecutive naturals, for example, 6059615 + ... + 6059724.

It is an arithmetic number, because the mean of its divisors is an integer number (109074060).

Almost surely, 2^666563645 is an apocalyptic number.

It is an amenable number.

666563645 is a deficient number, since it is larger than the sum of its proper divisors (206028835).

666563645 is a wasteful number, since it uses less digits than its factorization.

666563645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12119355.

The product of its digits is 2332800, while the sum is 47.

The square root of 666563645 is about 25817.8938916403. The cubic root of 666563645 is about 873.5354635604.

The spelling of 666563645 in words is "six hundred sixty-six million, five hundred sixty-three thousand, six hundred forty-five".