256505740065 has 64 divisors (see below), whose sum is σ = 482929413120. Its totient is φ = 128730470400.

The previous prime is 256505740009. The next prime is 256505740097. The reversal of 256505740065 is 560047505652.

256505740065 is a `hidden beast` number, since 25 + 6 + 50 + 574 + 0 + 0 + 6 + 5 = 666.

It is not a de Polignac number, because 256505740065 - 2¹⁷ = 256505608993 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 256505740065.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 18240517 + ... + 18254573.

It is an arithmetic number, because the mean of its divisors is an integer number (7545772080).

Almost surely, 2^256505740065 is an apocalyptic number.

It is an amenable number.

256505740065 is a deficient number, since it is larger than the sum of its proper divisors (226423673055).

256505740065 is a wasteful number, since it uses less digits than its factorization.

256505740065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22039 (or 22033 counting only the distinct ones).

The product of its (nonzero) digits is 1260000, while the sum is 45.

The spelling of 256505740065 in words is "two hundred fifty-six billion, five hundred five million, seven hundred forty thousand, sixty-five".