256776578565 has 32 divisors (see below), whose sum is σ = 450793848960. Its totient is φ = 124027927296.

The previous prime is 256776578551. The next prime is 256776578581. The reversal of 256776578565 is 565875677652.

It is not a de Polignac number, because 256776578565 - 2⁶ = 256776578501 is a prime.

It is a super-2 number, since 2×256776578565² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 256776578565.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12412335 + ... + 12433004.

It is an arithmetic number, because the mean of its divisors is an integer number (14087307780).

Almost surely, 2^256776578565 is an apocalyptic number.

It is an amenable number.

256776578565 is a deficient number, since it is larger than the sum of its proper divisors (194017270395).

256776578565 is a wasteful number, since it uses less digits than its factorization.

256776578565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24845413.

The product of its digits is 740880000, while the sum is 69.

The spelling of 256776578565 in words is "two hundred fifty-six billion, seven hundred seventy-six million, five hundred seventy-eight thousand, five hundred sixty-five".