256178664 has 72 divisors (see below), whose sum is σ = 807104610. Its totient is φ = 73192896.

The previous prime is 256178633. The next prime is 256178683. The reversal of 256178664 is 466871652.

256178664 is a `hidden beast` number, since 2 + 561 + 7 + 86 + 6 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 186322500 + 69856164 = 13650^2 + 8358^2 .

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

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 32779 + ... + 39834.

Almost surely, 2^256178664 is an apocalyptic number.

256178664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

256178664 is an abundant number, since it is smaller than the sum of its proper divisors (550925946).

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

256178664 is a wasteful number, since it uses less digits than its factorization.

256178664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72639 (or 72625 counting only the distinct ones).

The product of its digits is 483840, while the sum is 45.

The square root of 256178664 is about 16005.5822761935. The cubic root of 256178664 is about 635.1081007191.

It can be divided in two parts, 2561 and 78664, that added together give a square (81225 = 285²).

The spelling of 256178664 in words is "two hundred fifty-six million, one hundred seventy-eight thousand, six hundred sixty-four".