261843 has 4 divisors (see below), whose sum is σ = 349128. Its totient is φ = 174560.

The previous prime is 261823. The next prime is 261847. The reversal of 261843 is 348162.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 261843 - 2⁸ = 261587 is a prime.

It is a D-number.

261843 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (261847) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43638 + ... + 43643.

It is an arithmetic number, because the mean of its divisors is an integer number (87282).

2²⁶¹⁸⁴³ is an apocalyptic number.

261843 is a deficient number, since it is larger than the sum of its proper divisors (87285).

261843 is an equidigital number, since it uses as much as digits as its factorization.

261843 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87284.

The product of its digits is 1152, while the sum is 24.

The square root of 261843 is about 511.7059702603. The cubic root of 261843 is about 63.9754951759.

The spelling of 261843 in words is "two hundred sixty-one thousand, eight hundred forty-three".