256226681 has 2 divisors, whose sum is σ = 256226682. Its totient is φ = 256226680.

The previous prime is 256226603. The next prime is 256226683. The reversal of 256226681 is 186622652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 245204281 + 11022400 = 15659^2 + 3320^2 .

It is a cyclic number.

It is not a de Polignac number, because 256226681 - 2¹⁸ = 255964537 is a prime.

It is a super-2 number, since 2×256226681² = 131304224112551522, which contains 22 as substring.

Together with 256226683, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (256226683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128113340 + 128113341.

It is an arithmetic number, because the mean of its divisors is an integer number (128113341).

Almost surely, 2^256226681 is an apocalyptic number.

It is an amenable number.

256226681 is a deficient number, since it is larger than the sum of its proper divisors (1).

256226681 is an equidigital number, since it uses as much as digits as its factorization.

256226681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 69120, while the sum is 38.

The square root of 256226681 is about 16007.0822138202. The cubic root of 256226681 is about 635.1477788615.

The spelling of 256226681 in words is "two hundred fifty-six million, two hundred twenty-six thousand, six hundred eighty-one".