256338689 has 2 divisors, whose sum is σ = 256338690. Its totient is φ = 256338688.

The previous prime is 256338623. The next prime is 256338727. The reversal of 256338689 is 986833652.

256338689 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 252555664 + 3783025 = 15892^2 + 1945^2 .

It is a cyclic number.

It is not a de Polignac number, because 256338689 - 2²⁴ = 239561473 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (256338619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128169344 + 128169345.

It is an arithmetic number, because the mean of its divisors is an integer number (128169345).

Almost surely, 2^256338689 is an apocalyptic number.

It is an amenable number.

256338689 is a deficient number, since it is larger than the sum of its proper divisors (1).

256338689 is an equidigital number, since it uses as much as digits as its factorization.

256338689 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1866240, while the sum is 50.

The square root of 256338689 is about 16010.5805328851. The cubic root of 256338689 is about 635.2403157618.

The spelling of 256338689 in words is "two hundred fifty-six million, three hundred thirty-eight thousand, six hundred eighty-nine".