666505564 has 12 divisors (see below), whose sum is σ = 1167200944. Its totient is φ = 333019584.

The previous prime is 666505561. The next prime is 666505571. The reversal of 666505564 is 465505666.

666505564 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 666505564.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666505561) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51789 + ... + 63364.

Almost surely, 2^666505564 is an apocalyptic number.

It is an amenable number.

666505564 is a deficient number, since it is larger than the sum of its proper divisors (500695380).

666505564 is a wasteful number, since it uses less digits than its factorization.

666505564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116604 (or 116602 counting only the distinct ones).

The product of its (nonzero) digits is 648000, while the sum is 43.

The square root of 666505564 is about 25816.7690464938. The cubic root of 666505564 is about 873.5100909961.

The spelling of 666505564 in words is "six hundred sixty-six million, five hundred five thousand, five hundred sixty-four".