256550309 has 2 divisors, whose sum is σ = 256550310. Its totient is φ = 256550308.

The previous prime is 256550297. The next prime is 256550317. The reversal of 256550309 is 903055652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 169650625 + 86899684 = 13025^2 + 9322^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256550309 is a prime.

It is a super-2 number, since 2×256550309² = 131636122095990962, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256550909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128275154 + 128275155.

It is an arithmetic number, because the mean of its divisors is an integer number (128275155).

Almost surely, 2^256550309 is an apocalyptic number.

It is an amenable number.

256550309 is a deficient number, since it is larger than the sum of its proper divisors (1).

256550309 is an equidigital number, since it uses as much as digits as its factorization.

256550309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40500, while the sum is 35.

The square root of 256550309 is about 16017.1879242269. The cubic root of 256550309 is about 635.4150748932.

The spelling of 256550309 in words is "two hundred fifty-six million, five hundred fifty thousand, three hundred nine".