261807836871 has 48 divisors (see below), whose sum is σ = 424913369184. Its totient is φ = 142814520576.

The previous prime is 261807836837. The next prime is 261807836893. The reversal of 261807836871 is 178638708162.

It is not a de Polignac number, because 261807836871 - 2¹¹ = 261807834823 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261807836071) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 165840 + ... + 742373.

It is an arithmetic number, because the mean of its divisors is an integer number (8852361858).

Almost surely, 2^261807836871 is an apocalyptic number.

261807836871 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

261807836871 is a deficient number, since it is larger than the sum of its proper divisors (163105532313).

261807836871 is a wasteful number, since it uses less digits than its factorization.

261807836871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 908320 (or 908313 counting only the distinct ones).

The product of its (nonzero) digits is 5419008, while the sum is 57.

The spelling of 261807836871 in words is "two hundred sixty-one billion, eight hundred seven million, eight hundred thirty-six thousand, eight hundred seventy-one".