256761575561 has 8 divisors (see below), whose sum is σ = 261783372360. Its totient is φ = 251780441472.

The previous prime is 256761575471. The next prime is 256761575569. The reversal of 256761575561 is 165575167652.

256761575561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 23599104400 + 233162471161 = 153620^2 + 482869^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 256761575561 - 2¹⁴ = 256761559177 is a prime.

It is a super-2 number, since 2×256761575561² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 256761575497 and 256761575506.

It is not an unprimeable number, because it can be changed into a prime (256761575569) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 10152926 + ... + 10178183.

It is an arithmetic number, because the mean of its divisors is an integer number (32722921545).

Almost surely, 2^256761575561 is an apocalyptic number.

It is an amenable number.

256761575561 is a deficient number, since it is larger than the sum of its proper divisors (5021796799).

256761575561 is a wasteful number, since it uses less digits than its factorization.

256761575561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20331355.

The product of its digits is 13230000, while the sum is 56.

The spelling of 256761575561 in words is "two hundred fifty-six billion, seven hundred sixty-one million, five hundred seventy-five thousand, five hundred sixty-one".