278779 has 4 divisors (see below), whose sum is σ = 280800. Its totient is φ = 276760.

The previous prime is 278767. The next prime is 278801. The reversal of 278779 is 977872.

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 278779 - 2⁷ = 278651 is a prime.

It is a Duffinian number.

278779 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (278279) 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, 787 + ... + 1084.

It is an arithmetic number, because the mean of its divisors is an integer number (70200).

2²⁷⁸⁷⁷⁹ is an apocalyptic number.

278779 is a deficient number, since it is larger than the sum of its proper divisors (2021).

278779 is a wasteful number, since it uses less digits than its factorization.

278779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2020.

The product of its digits is 49392, while the sum is 40.

The square root of 278779 is about 527.9952651303. The cubic root of 278779 is about 65.3260930706.

The spelling of 278779 in words is "two hundred seventy-eight thousand, seven hundred seventy-nine".