261885 has 32 divisors (see below), whose sum is σ = 483840. Its totient is φ = 119808.

The previous prime is 261881. The next prime is 261887. The reversal of 261885 is 588162.

It is not a de Polignac number, because 261885 - 2² = 261881 is a prime.

It is a Curzon 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 31 ways as a sum of consecutive naturals, for example, 3276 + ... + 3354.

It is an arithmetic number, because the mean of its divisors is an integer number (15120).

261885 is a Friedman number, since it can be written as 8^6-251-8, using all its digits and the basic arithmetic operations.

2²⁶¹⁸⁸⁵ is an apocalyptic number.

It is an amenable number.

261885 is a deficient number, since it is larger than the sum of its proper divisors (221955).

261885 is a wasteful number, since it uses less digits than its factorization.

261885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117.

The product of its digits is 3840, while the sum is 30.

The square root of 261885 is about 511.7470078076. The cubic root of 261885 is about 63.9789155807.

The spelling of 261885 in words is "two hundred sixty-one thousand, eight hundred eighty-five".