256430866 has 4 divisors (see below), whose sum is σ = 384646302. Its totient is φ = 128215432.

The previous prime is 256430861. The next prime is 256430869. The reversal of 256430866 is 668034652.

It is a happy number.

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., 141491025 + 114939841 = 11895^2 + 10721^2 .

It is not an unprimeable number, because it can be changed into a prime (256430861) 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, 64107715 + ... + 64107718.

Almost surely, 2^256430866 is an apocalyptic number.

256430866 is a deficient number, since it is larger than the sum of its proper divisors (128215436).

256430866 is a wasteful number, since it uses less digits than its factorization.

256430866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128215435.

The product of its (nonzero) digits is 207360, while the sum is 40.

The square root of 256430866 is about 16013.4589018113. The cubic root of 256430866 is about 635.3164487998.

The spelling of 256430866 in words is "two hundred fifty-six million, four hundred thirty thousand, eight hundred sixty-six".