279861 has 4 divisors (see below), whose sum is σ = 373152. Its totient is φ = 186572.

The previous prime is 279857. The next prime is 279863. The reversal of 279861 is 168972.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 279861 - 2² = 279857 is a prime.

It is a D-number.

279861 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (279863) 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, 46641 + ... + 46646.

It is an arithmetic number, because the mean of its divisors is an integer number (93288).

279861 is a Friedman number, since it can be written as 6^7-9*8-2-1, using all its digits and the basic arithmetic operations.

2²⁷⁹⁸⁶¹ is an apocalyptic number.

It is an amenable number.

279861 is a deficient number, since it is larger than the sum of its proper divisors (93291).

279861 is an equidigital number, since it uses as much as digits as its factorization.

279861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93290.

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

The square root of 279861 is about 529.0189032539. The cubic root of 279861 is about 65.4104987401.

Subtracting from 279861 its reverse (168972), we obtain a square (110889 = 333²).

The spelling of 279861 in words is "two hundred seventy-nine thousand, eight hundred sixty-one".