666563646 has 32 divisors (see below), whose sum is σ = 1524987648. Its totient is φ = 190270080.

The previous prime is 666563641. The next prime is 666563687. The reversal of 666563646 is 646365666.

It is a junction number, because it is equal to n+sod(n) for n = 666563595 and 666563604.

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 15 ways as a sum of consecutive naturals, for example, 42406 + ... + 55958.

It is an arithmetic number, because the mean of its divisors is an integer number (47655864).

Almost surely, 2^666563646 is an apocalyptic number.

666563646 is an abundant number, since it is smaller than the sum of its proper divisors (858424002).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

666563646 is a wasteful number, since it uses less digits than its factorization.

666563646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14736.

The product of its digits is 2799360, while the sum is 48.

The square root of 666563646 is about 25817.8939110068. The cubic root of 666563646 is about 873.5354639973.

The spelling of 666563646 in words is "six hundred sixty-six million, five hundred sixty-three thousand, six hundred forty-six".