256336681 has 2 divisors, whose sum is σ = 256336682. Its totient is φ = 256336680.

The previous prime is 256336669. The next prime is 256336699. The reversal of 256336681 is 186633652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 236667456 + 19669225 = 15384^2 + 4435^2 .

It is a cyclic number.

It is not a de Polignac number, because 256336681 - 2⁵ = 256336649 is a prime.

It is a super-2 number, since 2×256336681² = 131416988052191522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (256336601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128168340 + 128168341.

It is an arithmetic number, because the mean of its divisors is an integer number (128168341).

Almost surely, 2^256336681 is an apocalyptic number.

It is an amenable number.

256336681 is a deficient number, since it is larger than the sum of its proper divisors (1).

256336681 is an equidigital number, since it uses as much as digits as its factorization.

256336681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 155520, while the sum is 40.

The square root of 256336681 is about 16010.5178242304. The cubic root of 256336681 is about 635.2386570632.

The spelling of 256336681 in words is "two hundred fifty-six million, three hundred thirty-six thousand, six hundred eighty-one".