261656311 has 4 divisors (see below), whose sum is σ = 299035792. Its totient is φ = 224276832.

The previous prime is 261656287. The next prime is 261656321. The reversal of 261656311 is 113656162.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 261656311 - 2⁵ = 261656279 is a prime.

It is a super-2 number, since 2×261656311² = 136928050172257442, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261656321) 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, 18689730 + ... + 18689743.

It is an arithmetic number, because the mean of its divisors is an integer number (74758948).

Almost surely, 2^261656311 is an apocalyptic number.

261656311 is a deficient number, since it is larger than the sum of its proper divisors (37379481).

261656311 is an equidigital number, since it uses as much as digits as its factorization.

261656311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37379480.

The product of its digits is 6480, while the sum is 31.

The square root of 261656311 is about 16175.7939836040. The cubic root of 261656311 is about 639.6028713030.

The spelling of 261656311 in words is "two hundred sixty-one million, six hundred fifty-six thousand, three hundred eleven".