256929809 has 2 divisors, whose sum is σ = 256929810. Its totient is φ = 256929808.

The previous prime is 256929779. The next prime is 256929833. The reversal of 256929809 is 908929652.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 205492225 + 51437584 = 14335^2 + 7172^2 .

It is a cyclic number.

It is not a de Polignac number, because 256929809 - 2⁸ = 256929553 is a prime.

It is not a weakly prime, because it can be changed into another prime (256920809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128464904 + 128464905.

It is an arithmetic number, because the mean of its divisors is an integer number (128464905).

Almost surely, 2^256929809 is an apocalyptic number.

It is an amenable number.

256929809 is a deficient number, since it is larger than the sum of its proper divisors (1).

256929809 is an equidigital number, since it uses as much as digits as its factorization.

256929809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 699840, while the sum is 50.

The square root of 256929809 is about 16029.0301952426. The cubic root of 256929809 is about 635.7282314277.

The spelling of 256929809 in words is "two hundred fifty-six million, nine hundred twenty-nine thousand, eight hundred nine".