256673740217 has 2 divisors, whose sum is σ = 256673740218. Its totient is φ = 256673740216.

The previous prime is 256673740189. The next prime is 256673740307. The reversal of 256673740217 is 712047376652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 161034466681 + 95639273536 = 401291^2 + 309256^2 .

It is a cyclic number.

It is not a de Polignac number, because 256673740217 - 2⁶ = 256673740153 is a prime.

It is not a weakly prime, because it can be changed into another prime (256673740717) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128336870108 + 128336870109.

It is an arithmetic number, because the mean of its divisors is an integer number (128336870109).

Almost surely, 2^256673740217 is an apocalyptic number.

It is an amenable number.

256673740217 is a deficient number, since it is larger than the sum of its proper divisors (1).

256673740217 is an equidigital number, since it uses as much as digits as its factorization.

256673740217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2963520, while the sum is 50.

The spelling of 256673740217 in words is "two hundred fifty-six billion, six hundred seventy-three million, seven hundred forty thousand, two hundred seventeen".