261879 has 4 divisors (see below), whose sum is σ = 349176. Its totient is φ = 174584.

The previous prime is 261847. The next prime is 261881. The reversal of 261879 is 978162.

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 261879 - 2⁵ = 261847 is a prime.

It is a super-2 number, since 2×261879² = 137161221282, which contains 22 as substring.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261379) 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, 43644 + ... + 43649.

It is an arithmetic number, because the mean of its divisors is an integer number (87294).

261879 is a Friedman number, since it can be written as 8^6-9-2^(7+1), using all its digits and the basic arithmetic operations.

2²⁶¹⁸⁷⁹ is an apocalyptic number.

261879 is a deficient number, since it is larger than the sum of its proper divisors (87297).

261879 is an equidigital number, since it uses as much as digits as its factorization.

261879 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87296.

The product of its digits is 6048, while the sum is 33.

The square root of 261879 is about 511.7411455023. The cubic root of 261879 is about 63.9784269738.

The spelling of 261879 in words is "two hundred sixty-one thousand, eight hundred seventy-nine".