261608559 has 8 divisors (see below), whose sum is σ = 348904752. Its totient is φ = 174359040.

The previous prime is 261608539. The next prime is 261608573. The reversal of 261608559 is 955806162.

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

It is not a de Polignac number, because 261608559 - 2⁹ = 261608047 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261608559.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261608519) 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, 4689 + ... + 23349.

It is an arithmetic number, because the mean of its divisors is an integer number (43613094).

Almost surely, 2^261608559 is an apocalyptic number.

261608559 is a deficient number, since it is larger than the sum of its proper divisors (87296193).

261608559 is a wasteful number, since it uses less digits than its factorization.

261608559 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23337.

The product of its (nonzero) digits is 129600, while the sum is 42.

The square root of 261608559 is about 16174.3178836080. The cubic root of 261608559 is about 639.5639599866.

The spelling of 261608559 in words is "two hundred sixty-one million, six hundred eight thousand, five hundred fifty-nine".