64666656 has 72 divisors (see below), whose sum is σ = 185238144. Its totient is φ = 21398400.

The previous prime is 64666643. The next prime is 64666661. The reversal of 64666656 is 65666646.

64666656 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (72).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 42745 + ... + 44231.

It is an arithmetic number, because the mean of its divisors is an integer number (2572752).

Almost surely, 2^64666656 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 64666656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (92619072).

64666656 is an abundant number, since it is smaller than the sum of its proper divisors (120571488).

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

64666656 is a wasteful number, since it uses less digits than its factorization.

64666656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1654 (or 1643 counting only the distinct ones).

The product of its digits is 933120, while the sum is 45.

The square root of 64666656 is about 8041.5580579885. The cubic root of 64666656 is about 401.3840720046.

The spelling of 64666656 in words is "sixty-four million, six hundred sixty-six thousand, six hundred fifty-six".