664166656 has 36 divisors (see below), whose sum is σ = 1327988844. Its totient is φ = 331520000.

The previous prime is 664166651. The next prime is 664166669. The reversal of 664166656 is 656661466.

It can be written as a sum of positive squares in 2 ways, for example, as 432640000 + 231526656 = 20800^2 + 15216^2 .

It is a super-2 number, since 2×664166656² = 882234693884444672, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (664166651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 177606 + ... + 181306.

It is an arithmetic number, because the mean of its divisors is an integer number (36888579).

Almost surely, 2^664166656 is an apocalyptic number.

It is an amenable number.

664166656 is a deficient number, since it is larger than the sum of its proper divisors (663822188).

664166656 is an equidigital number, since it uses as much as digits as its factorization.

664166656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4418 (or 4404 counting only the distinct ones).

The product of its digits is 933120, while the sum is 46.

The square root of 664166656 is about 25771.4310041177. The cubic root of 664166656 is about 872.4871166643.

The spelling of 664166656 in words is "six hundred sixty-four million, one hundred sixty-six thousand, six hundred fifty-six".