261115881 has 16 divisors (see below), whose sum is σ = 377805120. Its totient is φ = 159456960.

The previous prime is 261115873. The next prime is 261115889. The reversal of 261115881 is 188511162.

It is an interprime number because it is at equal distance from previous prime (261115873) and next prime (261115889).

It is not a de Polignac number, because 261115881 - 2³ = 261115873 is a prime.

It is a super-2 number, since 2×261115881² = 136363006620812322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (261115889) 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, 20446 + ... + 30663.

It is an arithmetic number, because the mean of its divisors is an integer number (23612820).

Almost surely, 2^261115881 is an apocalyptic number.

It is an amenable number.

261115881 is a deficient number, since it is larger than the sum of its proper divisors (116689239).

261115881 is a wasteful number, since it uses less digits than its factorization.

261115881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51256.

The product of its digits is 3840, while the sum is 33.

The square root of 261115881 is about 16159.0804503227. The cubic root of 261115881 is about 639.1622184101.

The spelling of 261115881 in words is "two hundred sixty-one million, one hundred fifteen thousand, eight hundred eighty-one".