256605563 has 2 divisors, whose sum is σ = 256605564. Its totient is φ = 256605562.

The previous prime is 256605533. The next prime is 256605607. The reversal of 256605563 is 365506652.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 256605563 - 2¹⁶ = 256540027 is a prime.

It is not a weakly prime, because it can be changed into another prime (256605533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128302781 + 128302782.

It is an arithmetic number, because the mean of its divisors is an integer number (128302782).

Almost surely, 2^256605563 is an apocalyptic number.

256605563 is a deficient number, since it is larger than the sum of its proper divisors (1).

256605563 is an equidigital number, since it uses as much as digits as its factorization.

256605563 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 162000, while the sum is 38.

The square root of 256605563 is about 16018.9126659708. The cubic root of 256605563 is about 635.4606886943.

The spelling of 256605563 in words is "two hundred fifty-six million, six hundred five thousand, five hundred sixty-three".