261873 has 20 divisors (see below), whose sum is σ = 405108. Its totient is φ = 168480.

The previous prime is 261847. The next prime is 261881. The reversal of 261873 is 378162.

It can be written as a sum of positive squares in 2 ways, for example, as 82944 + 178929 = 288^2 + 423^2 .

It is not a de Polignac number, because 261873 - 2¹⁰ = 260849 is a prime.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

Its product of digits (2016) is a multiple of the sum of its prime factors (126).

261873 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (261823) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 4263 + ... + 4323.

2²⁶¹⁸⁷³ is an apocalyptic number.

It is an amenable number.

261873 is a deficient number, since it is larger than the sum of its proper divisors (143235).

261873 is an equidigital number, since it uses as much as digits as its factorization.

261873 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126 (or 117 counting only the distinct ones).

The product of its digits is 2016, while the sum is 27.

The square root of 261873 is about 511.7352831299. The cubic root of 261873 is about 63.9779383595.

The spelling of 261873 in words is "two hundred sixty-one thousand, eight hundred seventy-three".