256668413 has 2 divisors, whose sum is σ = 256668414. Its totient is φ = 256668412.

The previous prime is 256668389. The next prime is 256668421. The reversal of 256668413 is 314866652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 224610169 + 32058244 = 14987^2 + 5662^2 .

It is a cyclic number.

It is not a de Polignac number, because 256668413 - 2⁸ = 256668157 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256668463) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128334206 + 128334207.

It is an arithmetic number, because the mean of its divisors is an integer number (128334207).

Almost surely, 2^256668413 is an apocalyptic number.

It is an amenable number.

256668413 is a deficient number, since it is larger than the sum of its proper divisors (1).

256668413 is an equidigital number, since it uses as much as digits as its factorization.

256668413 is an evil number, because the sum of its binary digits is even.

The product of its digits is 207360, while the sum is 41.

The square root of 256668413 is about 16020.8742895012. The cubic root of 256668413 is about 635.5125652574.

The spelling of 256668413 in words is "two hundred fifty-six million, six hundred sixty-eight thousand, four hundred thirteen".