259521561 has 24 divisors (see below), whose sum is σ = 404267136. Its totient is φ = 159481440.

The previous prime is 259521533. The next prime is 259521569. The reversal of 259521561 is 165125952.

259521561 is a `hidden beast` number, since 2 + 5 + 95 + 2 + 1 + 561 = 666.

It is not a de Polignac number, because 259521561 - 2⁷ = 259521433 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (259521569) 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 23 ways as a sum of consecutive naturals, for example, 128046 + ... + 130056.

It is an arithmetic number, because the mean of its divisors is an integer number (16844464).

Almost surely, 2^259521561 is an apocalyptic number.

It is an amenable number.

259521561 is a deficient number, since it is larger than the sum of its proper divisors (144745575).

259521561 is a wasteful number, since it uses less digits than its factorization.

259521561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3133 (or 3130 counting only the distinct ones).

The product of its digits is 27000, while the sum is 36.

The square root of 259521561 is about 16109.6729017072. The cubic root of 259521561 is about 637.8586973292.

The spelling of 259521561 in words is "two hundred fifty-nine million, five hundred twenty-one thousand, five hundred sixty-one".