6646664 has 8 divisors (see below), whose sum is σ = 12462510. Its totient is φ = 3323328.

The previous prime is 6646663. The next prime is 6646669. The reversal of 6646664 is 4666466.

6646664 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 6461764 + 184900 = 2542^2 + 430^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (6646663) 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 as a sum of consecutive naturals, namely, 415409 + ... + 415424.

Almost surely, 2^6646664 is an apocalyptic number.

It is an amenable number.

6646664 is a deficient number, since it is larger than the sum of its proper divisors (5815846).

6646664 is a wasteful number, since it uses less digits than its factorization.

6646664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 830839 (or 830835 counting only the distinct ones).

The product of its digits is 124416, while the sum is 38.

The square root of 6646664 is about 2578.1124878484. The cubic root of 6646664 is about 188.0187849043.

The spelling of 6646664 in words is "six million, six hundred forty-six thousand, six hundred sixty-four".