64686388 has 12 divisors (see below), whose sum is σ = 121909060. Its totient is φ = 29855232.

The previous prime is 64686371. The next prime is 64686389. The reversal of 64686388 is 88368646.

64686388 is digitally balanced in base 2, 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 2 ways, for example, as 32741284 + 31945104 = 5722^2 + 5652^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64686389) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 621933 + ... + 622036.

Almost surely, 2^64686388 is an apocalyptic number.

It is an amenable number.

64686388 is a deficient number, since it is larger than the sum of its proper divisors (57222672).

64686388 is a wasteful number, since it uses less digits than its factorization.

64686388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1243986 (or 1243984 counting only the distinct ones).

The product of its digits is 1327104, while the sum is 49.

The square root of 64686388 is about 8042.7848410858. The cubic root of 64686388 is about 401.4248931716.

It can be divided in two parts, 6468638 and 8, that added together give a palindrome (6468646).

The spelling of 64686388 in words is "sixty-four million, six hundred eighty-six thousand, three hundred eighty-eight".