256305866 has 4 divisors (see below), whose sum is σ = 384458802. Its totient is φ = 128152932.

The previous prime is 256305851. The next prime is 256305869. The reversal of 256305866 is 668503652.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 245580241 + 10725625 = 15671^2 + 3275^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (256305869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64076465 + ... + 64076468.

Almost surely, 2^256305866 is an apocalyptic number.

256305866 is a deficient number, since it is larger than the sum of its proper divisors (128152936).

256305866 is a wasteful number, since it uses less digits than its factorization.

256305866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128152935.

The product of its (nonzero) digits is 259200, while the sum is 41.

The square root of 256305866 is about 16009.5554591625. Note that the first 3 decimals coincide. The cubic root of 256305866 is about 635.2132013961.

The spelling of 256305866 in words is "two hundred fifty-six million, three hundred five thousand, eight hundred sixty-six".