256778311 has 2 divisors, whose sum is σ = 256778312. Its totient is φ = 256778310.

The previous prime is 256778273. The next prime is 256778317. The reversal of 256778311 is 113877652.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 256778311 - 2¹⁷ = 256647239 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256778317) 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, 128389155 + 128389156.

It is an arithmetic number, because the mean of its divisors is an integer number (128389156).

Almost surely, 2^256778311 is an apocalyptic number.

256778311 is a deficient number, since it is larger than the sum of its proper divisors (1).

256778311 is an equidigital number, since it uses as much as digits as its factorization.

256778311 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 70560, while the sum is 40.

The square root of 256778311 is about 16024.3037602262. The cubic root of 256778311 is about 635.6032550225.

The spelling of 256778311 in words is "two hundred fifty-six million, seven hundred seventy-eight thousand, three hundred eleven".