256205969 has 2 divisors, whose sum is σ = 256205970. Its totient is φ = 256205968.

The previous prime is 256205959. The next prime is 256206017. The reversal of 256205969 is 969502652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 193210000 + 62995969 = 13900^2 + 7937^2 .

It is a cyclic number.

It is not a de Polignac number, because 256205969 - 2⁸ = 256205713 is a prime.

It is a super-2 number, since 2×256205969² = 131282997102457922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (256205959) 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, 128102984 + 128102985.

It is an arithmetic number, because the mean of its divisors is an integer number (128102985).

Almost surely, 2^256205969 is an apocalyptic number.

It is an amenable number.

256205969 is a deficient number, since it is larger than the sum of its proper divisors (1).

256205969 is an equidigital number, since it uses as much as digits as its factorization.

256205969 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 291600, while the sum is 44.

The square root of 256205969 is about 16006.4352371164. The cubic root of 256205969 is about 635.1306644126.

The spelling of 256205969 in words is "two hundred fifty-six million, two hundred five thousand, nine hundred sixty-nine".