279985 has 4 divisors (see below), whose sum is σ = 335988. Its totient is φ = 223984.

The previous prime is 279977. The next prime is 279991. The reversal of 279985 is 589972.

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 106929 + 173056 = 327^2 + 416^2 .

It is a cyclic number.

It is not a de Polignac number, because 279985 - 2³ = 279977 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27994 + ... + 28003.

It is an arithmetic number, because the mean of its divisors is an integer number (83997).

2²⁷⁹⁹⁸⁵ is an apocalyptic number.

It is an amenable number.

279985 is a deficient number, since it is larger than the sum of its proper divisors (56003).

279985 is an equidigital number, since it uses as much as digits as its factorization.

279985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56002.

The product of its digits is 45360, while the sum is 40.

The square root of 279985 is about 529.1360883553. The cubic root of 279985 is about 65.4201579449.

The spelling of 279985 in words is "two hundred seventy-nine thousand, nine hundred eighty-five".