261116611 has 4 divisors (see below), whose sum is σ = 298418992. Its totient is φ = 223814232.

The previous prime is 261116593. The next prime is 261116633. The reversal of 261116611 is 116611162.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 116611162 = 2 ⋅58305581.

It is a cyclic number.

It is not a de Polignac number, because 261116611 - 2⁵ = 261116579 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261116711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18651180 + ... + 18651193.

It is an arithmetic number, because the mean of its divisors is an integer number (74604748).

Almost surely, 2^261116611 is an apocalyptic number.

261116611 is a deficient number, since it is larger than the sum of its proper divisors (37302381).

261116611 is an equidigital number, since it uses as much as digits as its factorization.

261116611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37302380.

The product of its digits is 432, while the sum is 25.

The square root of 261116611 is about 16159.1030382259. The cubic root of 261116611 is about 639.1628140434.

Adding to 261116611 its reverse (116611162), we get a palindrome (377727773).

The spelling of 261116611 in words is "two hundred sixty-one million, one hundred sixteen thousand, six hundred eleven".