279665 has 4 divisors (see below), whose sum is σ = 335604. Its totient is φ = 223728.

The previous prime is 279659. The next prime is 279679. The reversal of 279665 is 566972.

279665 is nontrivially palindromic in base 13.

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

It can be written as a sum of positive squares in 2 ways, for example, as 78961 + 200704 = 281^2 + 448^2 .

It is a cyclic number.

It is not a de Polignac number, because 279665 - 2⁴ = 279649 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 279665.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27962 + ... + 27971.

It is an arithmetic number, because the mean of its divisors is an integer number (83901).

2²⁷⁹⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

279665 is a deficient number, since it is larger than the sum of its proper divisors (55939).

279665 is an equidigital number, since it uses as much as digits as its factorization.

279665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55938.

The product of its digits is 22680, while the sum is 35.

The square root of 279665 is about 528.8336222291. The cubic root of 279665 is about 65.3952251437.

It can be divided in two parts, 2 and 79665, that multiplied together give a triangular number (159330 = T₅₆₄).

The spelling of 279665 in words is "two hundred seventy-nine thousand, six hundred sixty-five".