256641779 has 2 divisors, whose sum is σ = 256641780. Its totient is φ = 256641778.

The previous prime is 256641773. The next prime is 256641821. The reversal of 256641779 is 977146652.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 256641779 - 2⁸ = 256641523 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (256641773) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128320889 + 128320890.

It is an arithmetic number, because the mean of its divisors is an integer number (128320890).

Almost surely, 2^256641779 is an apocalyptic number.

256641779 is a deficient number, since it is larger than the sum of its proper divisors (1).

256641779 is an equidigital number, since it uses as much as digits as its factorization.

256641779 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 635040, while the sum is 47.

The square root of 256641779 is about 16020.0430398922. The cubic root of 256641779 is about 635.4905825145.

The spelling of 256641779 in words is "two hundred fifty-six million, six hundred forty-one thousand, seven hundred seventy-nine".