261189 has 6 divisors (see below), whose sum is σ = 377286. Its totient is φ = 174120.

The previous prime is 261169. The next prime is 261223. The reversal of 261189 is 981162.

It can be written as a sum of positive squares in only one way, i.e., 260100 + 1089 = 510^2 + 33^2 .

It is not a de Polignac number, because 261189 - 2⁷ = 261061 is a prime.

261189 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261169) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 14502 + ... + 14519.

It is an arithmetic number, because the mean of its divisors is an integer number (62881).

2²⁶¹¹⁸⁹ is an apocalyptic number.

It is an amenable number.

261189 is a deficient number, since it is larger than the sum of its proper divisors (116097).

261189 is a wasteful number, since it uses less digits than its factorization.

261189 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29027 (or 29024 counting only the distinct ones).

The product of its digits is 864, while the sum is 27.

The square root of 261189 is about 511.0665318723. The cubic root of 261189 is about 63.9221873330.

Subtracting from 261189 its sum of digits (27), we obtain a palindrome (261162).

The spelling of 261189 in words is "two hundred sixty-one thousand, one hundred eighty-nine".