256500356617665 has 24 divisors (see below), whose sum is σ = 444604957667520. Its totient is φ = 136798854956064.

The previous prime is 256500356617649. The next prime is 256500356617691. The reversal of 256500356617665 is 566716653005652.

256500356617665 is a `hidden beast` number, since 2 + 5 + 6 + 5 + 0 + 0 + 3 + 5 + 6 + 617 + 6 + 6 + 5 = 666.

It is not a de Polignac number, because 256500356617665 - 2⁴ = 256500356617649 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 23147245 + ... + 32385114.

It is an arithmetic number, because the mean of its divisors is an integer number (18525206569480).

Almost surely, 2^{256500356617665} is an apocalyptic number.

It is an amenable number.

256500356617665 is a deficient number, since it is larger than the sum of its proper divisors (188104601049855).

256500356617665 is a wasteful number, since it uses less digits than its factorization.

256500356617665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55635013 (or 55635010 counting only the distinct ones).

The product of its (nonzero) digits is 204120000, while the sum is 63.

The spelling of 256500356617665 in words is "two hundred fifty-six trillion, five hundred billion, three hundred fifty-six million, six hundred seventeen thousand, six hundred sixty-five".