261087881 has 4 divisors (see below), whose sum is σ = 272439552. Its totient is φ = 249736212.

The previous prime is 261087863. The next prime is 261087889. The reversal of 261087881 is 188780162.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261087881 is a prime.

It is a super-2 number, since 2×261087881² = 136333763210140322, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (261087889) 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, 5675801 + ... + 5675846.

It is an arithmetic number, because the mean of its divisors is an integer number (68109888).

Almost surely, 2^261087881 is an apocalyptic number.

It is an amenable number.

261087881 is a deficient number, since it is larger than the sum of its proper divisors (11351671).

261087881 is a wasteful number, since it uses less digits than its factorization.

261087881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11351670.

The product of its (nonzero) digits is 43008, while the sum is 41.

The square root of 261087881 is about 16158.2140411619. The cubic root of 261087881 is about 639.1393713612.

The spelling of 261087881 in words is "two hundred sixty-one million, eighty-seven thousand, eight hundred eighty-one".