261165 has 16 divisors (see below), whose sum is σ = 436608. Its totient is φ = 133056.

The previous prime is 261127. The next prime is 261167. The reversal of 261165 is 561162.

It is a happy number.

It is not a de Polignac number, because 261165 - 2⁶ = 261101 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261167) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34 + ... + 723.

It is an arithmetic number, because the mean of its divisors is an integer number (27288).

2²⁶¹¹⁶⁵ is an apocalyptic number.

It is an amenable number.

261165 is a deficient number, since it is larger than the sum of its proper divisors (175443).

261165 is a wasteful number, since it uses less digits than its factorization.

261165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 788.

The product of its digits is 360, while the sum is 21.

The square root of 261165 is about 511.0430510241. The cubic root of 261165 is about 63.9202293900.

The spelling of 261165 in words is "two hundred sixty-one thousand, one hundred sixty-five".