261785265 has 16 divisors (see below), whose sum is σ = 478693248. Its totient is φ = 119673216.

The previous prime is 261785207. The next prime is 261785269. The reversal of 261785265 is 562587162.

It is not a de Polignac number, because 261785265 - 2⁹ = 261784753 is a prime.

It is a super-2 number, since 2×261785265² = 137063049942240450, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (261785269) 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, 1246492 + ... + 1246701.

It is an arithmetic number, because the mean of its divisors is an integer number (29918328).

Almost surely, 2^261785265 is an apocalyptic number.

It is an amenable number.

261785265 is a deficient number, since it is larger than the sum of its proper divisors (216907983).

261785265 is a wasteful number, since it uses less digits than its factorization.

261785265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2493208.

The product of its digits is 201600, while the sum is 42.

The square root of 261785265 is about 16179.7795102406. The cubic root of 261785265 is about 639.7079274387.

The spelling of 261785265 in words is "two hundred sixty-one million, seven hundred eighty-five thousand, two hundred sixty-five".