256557841 has 2 divisors, whose sum is σ = 256557842. Its totient is φ = 256557840.

The previous prime is 256557827. The next prime is 256557881. The reversal of 256557841 is 148755652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 136983616 + 119574225 = 11704^2 + 10935^2 .

It is a cyclic number.

It is not a de Polignac number, because 256557841 - 2⁷ = 256557713 is a prime.

It is not a weakly prime, because it can be changed into another prime (256557881) 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, 128278920 + 128278921.

It is an arithmetic number, because the mean of its divisors is an integer number (128278921).

Almost surely, 2^256557841 is an apocalyptic number.

It is an amenable number.

256557841 is a deficient number, since it is larger than the sum of its proper divisors (1).

256557841 is an equidigital number, since it uses as much as digits as its factorization.

256557841 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 336000, while the sum is 43.

The square root of 256557841 is about 16017.4230449221. The cubic root of 256557841 is about 635.4212931661.

It can be divided in two parts, 2565 and 57841, that added together give a palindrome (60406).

The spelling of 256557841 in words is "two hundred fifty-six million, five hundred fifty-seven thousand, eight hundred forty-one".