261365855 has 16 divisors (see below), whose sum is σ = 319152960. Its totient is φ = 205446912.

The previous prime is 261365851. The next prime is 261365869. The reversal of 261365855 is 558563162.

261365855 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 261365855 - 2² = 261365851 is a prime.

It is a super-2 number, since 2×261365855² = 136624220319762050, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261365851) 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, 72557 + ... + 76073.

It is an arithmetic number, because the mean of its divisors is an integer number (19947060).

Almost surely, 2^261365855 is an apocalyptic number.

261365855 is a deficient number, since it is larger than the sum of its proper divisors (57787105).

261365855 is a wasteful number, since it uses less digits than its factorization.

261365855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3778.

The product of its digits is 216000, while the sum is 41.

The square root of 261365855 is about 16166.8133842140. The cubic root of 261365855 is about 639.3661163594.

The spelling of 261365855 in words is "two hundred sixty-one million, three hundred sixty-five thousand, eight hundred fifty-five".