259817561 has 4 divisors (see below), whose sum is σ = 259971300. Its totient is φ = 259663824.

The previous prime is 259817557. The next prime is 259817563. The reversal of 259817561 is 165718952.

259817561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 104939536 + 154878025 = 10244^2 + 12445^2 .

It is a cyclic number.

It is not a de Polignac number, because 259817561 - 2² = 259817557 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (259817563) 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, 74306 + ... + 77723.

It is an arithmetic number, because the mean of its divisors is an integer number (64992825).

Almost surely, 2^259817561 is an apocalyptic number.

It is an amenable number.

259817561 is a deficient number, since it is larger than the sum of its proper divisors (153739).

259817561 is a wasteful number, since it uses less digits than its factorization.

259817561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153738.

The product of its digits is 151200, while the sum is 44.

The square root of 259817561 is about 16118.8573106160. The cubic root of 259817561 is about 638.1011106346.

The spelling of 259817561 in words is "two hundred fifty-nine million, eight hundred seventeen thousand, five hundred sixty-one".