261569513855 has 16 divisors (see below), whose sum is σ = 338221932384. Its totient is φ = 193048375680.

The previous prime is 261569513851. The next prime is 261569513969. The reversal of 261569513855 is 558315965162.

It is not a de Polignac number, because 261569513855 - 2² = 261569513851 is a prime.

It is a super-2 number, since 2×261569513855² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261569513855.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261569513851) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1038176 + ... + 1265285.

It is an arithmetic number, because the mean of its divisors is an integer number (21138870774).

Almost surely, 2^261569513855 is an apocalyptic number.

261569513855 is a deficient number, since it is larger than the sum of its proper divisors (76652418529).

261569513855 is a wasteful number, since it uses less digits than its factorization.

261569513855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2305226.

The product of its digits is 9720000, while the sum is 56.

The spelling of 261569513855 in words is "two hundred sixty-one billion, five hundred sixty-nine million, five hundred thirteen thousand, eight hundred fifty-five".