256025561 has 4 divisors (see below), whose sum is σ = 279300624. Its totient is φ = 232750500.

The previous prime is 256025557. The next prime is 256025597. The reversal of 256025561 is 165520652.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 256025561 - 2² = 256025557 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (256025531) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11637515 + ... + 11637536.

It is an arithmetic number, because the mean of its divisors is an integer number (69825156).

Almost surely, 2^256025561 is an apocalyptic number.

It is an amenable number.

256025561 is a deficient number, since it is larger than the sum of its proper divisors (23275063).

256025561 is a wasteful number, since it uses less digits than its factorization.

256025561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23275062.

The product of its (nonzero) digits is 18000, while the sum is 32.

The square root of 256025561 is about 16000.7987613119. The cubic root of 256025561 is about 634.9815531872.

The spelling of 256025561 in words is "two hundred fifty-six million, twenty-five thousand, five hundred sixty-one".