64400656 has 10 divisors (see below), whose sum is σ = 124776302. Its totient is φ = 32200320.

The previous prime is 64400617. The next prime is 64400659. The reversal of 64400656 is 65600446.

64400656 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 only one way, i.e., 64256256 + 144400 = 8016^2 + 380^2 .

It is not an unprimeable number, because it can be changed into a prime (64400659) 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 as a sum of consecutive naturals, namely, 2012505 + ... + 2012536.

Almost surely, 2^64400656 is an apocalyptic number.

It is an amenable number.

64400656 is a deficient number, since it is larger than the sum of its proper divisors (60375646).

64400656 is a wasteful number, since it uses less digits than its factorization.

64400656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4025049 (or 4025043 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 31.

The square root of 64400656 is about 8025.0019314639. The cubic root of 64400656 is about 400.8329642225.

Subtracting from 64400656 its sum of digits (31), we obtain a square (64400625 = 8025²).

It can be divided in two parts, 64400 and 656, that added together give a palindrome (65056).

The spelling of 64400656 in words is "sixty-four million, four hundred thousand, six hundred fifty-six".