278399 has 4 divisors (see below), whose sum is σ = 303720. Its totient is φ = 253080.

The previous prime is 278393. The next prime is 278413. The reversal of 278399 is 993872.

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 278399 - 2⁸ = 278143 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 13.

It is a zygodrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (278393) 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, 12644 + ... + 12665.

It is an arithmetic number, because the mean of its divisors is an integer number (75930).

2²⁷⁸³⁹⁹ is an apocalyptic number.

278399 is a deficient number, since it is larger than the sum of its proper divisors (25321).

278399 is a wasteful number, since it uses less digits than its factorization.

278399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25320.

The product of its digits is 27216, while the sum is 38.

The square root of 278399 is about 527.6352907075. The cubic root of 278399 is about 65.2963978604.

It can be divided in two parts, 2783 and 99, that added together give a palindrome (2882).

The spelling of 278399 in words is "two hundred seventy-eight thousand, three hundred ninety-nine".