261871 has 4 divisors (see below), whose sum is σ = 263032. Its totient is φ = 260712.

The previous prime is 261847. The next prime is 261881. The reversal of 261871 is 178162.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 261871 - 2¹¹ = 259823 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261881) 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, 120 + ... + 733.

It is an arithmetic number, because the mean of its divisors is an integer number (65758).

2²⁶¹⁸⁷¹ is an apocalyptic number.

261871 is a deficient number, since it is larger than the sum of its proper divisors (1161).

261871 is an equidigital number, since it uses as much as digits as its factorization.

261871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1160.

The product of its digits is 672, while the sum is 25.

The square root of 261871 is about 511.7333289908. The cubic root of 261871 is about 63.9777754864.

The spelling of 261871 in words is "two hundred sixty-one thousand, eight hundred seventy-one".