256735943909 has 2 divisors, whose sum is σ = 256735943910. Its totient is φ = 256735943908.

The previous prime is 256735943887. The next prime is 256735943917. The reversal of 256735943909 is 909349537652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 211131060100 + 45604883809 = 459490^2 + 213553^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256735943909 is a prime.

It is a super-3 number, since 3×256735943909³ (a number of 35 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256735943209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128367971954 + 128367971955.

It is an arithmetic number, because the mean of its divisors is an integer number (128367971955).

Almost surely, 2^256735943909 is an apocalyptic number.

It is an amenable number.

256735943909 is a deficient number, since it is larger than the sum of its proper divisors (1).

256735943909 is an equidigital number, since it uses as much as digits as its factorization.

256735943909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 55112400, while the sum is 62.

The spelling of 256735943909 in words is "two hundred fifty-six billion, seven hundred thirty-five million, nine hundred forty-three thousand, nine hundred nine".