261265082261 has 4 divisors (see below), whose sum is σ = 264944872224. Its totient is φ = 257585292300.

The previous prime is 261265082237. The next prime is 261265082297. The reversal of 261265082261 is 162280562162.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 162280562162 = 2 ⋅81140281081.

It is a cyclic number.

It is not a de Polignac number, because 261265082261 - 2¹⁰ = 261265081237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261265022261) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1839894875 + ... + 1839895016.

It is an arithmetic number, because the mean of its divisors is an integer number (66236218056).

Almost surely, 2^261265082261 is an apocalyptic number.

It is an amenable number.

261265082261 is a deficient number, since it is larger than the sum of its proper divisors (3679789963).

261265082261 is an equidigital number, since it uses as much as digits as its factorization.

261265082261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3679789962.

The product of its (nonzero) digits is 138240, while the sum is 41.

The spelling of 261265082261 in words is "two hundred sixty-one billion, two hundred sixty-five million, eighty-two thousand, two hundred sixty-one".