64778394256 has 15 divisors (see below), whose sum is σ = 125510111401. Its totient is φ = 32388688096.

The previous prime is 64778394203. The next prime is 64778394259. The reversal of 64778394256 is 65249387746.

The square root of 64778394256 is 254516.

It is a perfect power (a square), and thus also a powerful number.

64778394256 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., 24874336656 + 39904057600 = 157716^2 + 199760^2 .

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 64778394194 and 64778394203.

It is not an unprimeable number, because it can be changed into a prime (64778394259) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 986250 + ... + 1049878.

Almost surely, 2^64778394256 is an apocalyptic number.

64778394256 is the 254516-th square number.

It is an amenable number.

64778394256 is a deficient number, since it is larger than the sum of its proper divisors (60731717145).

64778394256 is an frugal number, since it uses more digits than its factorization.

64778394256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127266 (or 63631 counting only the distinct ones).

The product of its digits is 60963840, while the sum is 61.

The spelling of 64778394256 in words is "sixty-four billion, seven hundred seventy-eight million, three hundred ninety-four thousand, two hundred fifty-six".