261265 has 4 divisors (see below), whose sum is σ = 313524. Its totient is φ = 209008.

The previous prime is 261251. The next prime is 261271. The reversal of 261265 is 562162.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 562162 = 2 ⋅281081.

It can be written as a sum of positive squares in 2 ways, for example, as 88209 + 173056 = 297^2 + 416^2 .

It is a cyclic number.

It is not a de Polignac number, because 261265 - 2⁹ = 260753 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

261265 is a lucky number.

It is a nialpdrome in base 6 and base 8.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26122 + ... + 26131.

It is an arithmetic number, because the mean of its divisors is an integer number (78381).

2²⁶¹²⁶⁵ is an apocalyptic number.

It is an amenable number.

261265 is a deficient number, since it is larger than the sum of its proper divisors (52259).

261265 is an equidigital number, since it uses as much as digits as its factorization.

261265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52258.

The product of its digits is 720, while the sum is 22.

The square root of 261265 is about 511.1408807755. The cubic root of 261265 is about 63.9283866945.

The spelling of 261265 in words is "two hundred sixty-one thousand, two hundred sixty-five".