261140865 has 16 divisors (see below), whose sum is σ = 418387200. Its totient is φ = 139087872.

The previous prime is 261140861. The next prime is 261140879. The reversal of 261140865 is 568041162.

It is not a de Polignac number, because 261140865 - 2² = 261140861 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261140861) 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, 216 + ... + 22854.

It is an arithmetic number, because the mean of its divisors is an integer number (26149200).

Almost surely, 2^261140865 is an apocalyptic number.

It is an amenable number.

261140865 is a deficient number, since it is larger than the sum of its proper divisors (157246335).

261140865 is a wasteful number, since it uses less digits than its factorization.

261140865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23416.

The product of its (nonzero) digits is 11520, while the sum is 33.

The square root of 261140865 is about 16159.8534956230. The cubic root of 261140865 is about 639.1826031265.

The spelling of 261140865 in words is "two hundred sixty-one million, one hundred forty thousand, eight hundred sixty-five".