261265243 has 4 divisors (see below), whose sum is σ = 267637608. Its totient is φ = 254892880.

The previous prime is 261265229. The next prime is 261265253. The reversal of 261265243 is 342562162.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 342562162 = 2 ⋅171281081.

It is a cyclic number.

It is not a de Polignac number, because 261265243 - 2²⁵ = 227710811 is a prime.

It is a Smith number, since the sum of its digits (31) 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.

It is not an unprimeable number, because it can be changed into a prime (261265223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3186121 + ... + 3186202.

It is an arithmetic number, because the mean of its divisors is an integer number (66909402).

Almost surely, 2^261265243 is an apocalyptic number.

261265243 is a deficient number, since it is larger than the sum of its proper divisors (6372365).

261265243 is an equidigital number, since it uses as much as digits as its factorization.

261265243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6372364.

The product of its digits is 17280, while the sum is 31.

The square root of 261265243 is about 16163.7014015973. The cubic root of 261265243 is about 639.2840651420.

The spelling of 261265243 in words is "two hundred sixty-one million, two hundred sixty-five thousand, two hundred forty-three".