261711 has 14 divisors (see below), whose sum is σ = 393480. Its totient is φ = 173988.

The previous prime is 261707. The next prime is 261713. The reversal of 261711 is 117162.

It is not a de Polignac number, because 261711 - 2² = 261707 is a prime.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261713) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 550 + ... + 908.

2²⁶¹⁷¹¹ is an apocalyptic number.

261711 is a deficient number, since it is larger than the sum of its proper divisors (131769).

261711 is an frugal number, since it uses more digits than its factorization.

261711 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 377 (or 362 counting only the distinct ones).

The product of its digits is 84, while the sum is 18.

The square root of 261711 is about 511.5769736804. The cubic root of 261711 is about 63.9647429506.

Adding to 261711 its reverse (117162), we get a palindrome (378873).

It can be divided in two parts, 2617 and 11, that added together give a triangular number (2628 = T₇₂).

The spelling of 261711 in words is "two hundred sixty-one thousand, seven hundred eleven".