261943 has 4 divisors (see below), whose sum is σ = 285768. Its totient is φ = 238120.

The previous prime is 261917. The next prime is 261959. The reversal of 261943 is 349162.

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 261943 - 2⁹ = 261431 is a prime.

It is a super-2 number, since 2×261943² = 137228270498, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261973) 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, 11896 + ... + 11917.

It is an arithmetic number, because the mean of its divisors is an integer number (71442).

2²⁶¹⁹⁴³ is an apocalyptic number.

261943 is a deficient number, since it is larger than the sum of its proper divisors (23825).

261943 is a wasteful number, since it uses less digits than its factorization.

261943 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23824.

The product of its digits is 1296, while the sum is 25.

The square root of 261943 is about 511.8036732967. The cubic root of 261943 is about 63.9836383956.

It can be divided in two parts, 2619 and 43, that added together give a palindrome (2662).

The spelling of 261943 in words is "two hundred sixty-one thousand, nine hundred forty-three".