256563420065 has 12 divisors (see below), whose sum is σ = 318858610044. Its totient is φ = 198173121216.

The previous prime is 256563420053. The next prime is 256563420077. The reversal of 256563420065 is 560024365652.

It is an interprime number because it is at equal distance from previous prime (256563420053) and next prime (256563420077).

It can be written as a sum of positive squares in 6 ways, for example, as 369523729 + 256193896336 = 19223^2 + 506156^2 .

It is not a de Polignac number, because 256563420065 - 2⁸ = 256563419809 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 256563419998 and 256563420025.

It is an unprimeable number.

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 in 11 ways as a sum of consecutive naturals, for example, 30502742 + ... + 30511151.

It is an arithmetic number, because the mean of its divisors is an integer number (26571550837).

Almost surely, 2^256563420065 is an apocalyptic number.

It is an amenable number.

256563420065 is a deficient number, since it is larger than the sum of its proper divisors (62295189979).

256563420065 is an equidigital number, since it uses as much as digits as its factorization.

256563420065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61013956 (or 61013927 counting only the distinct ones).

The product of its (nonzero) digits is 1296000, while the sum is 44.

The spelling of 256563420065 in words is "two hundred fifty-six billion, five hundred sixty-three million, four hundred twenty thousand, sixty-five".