278813 has 2 divisors, whose sum is σ = 278814. Its totient is φ = 278812.

The previous prime is 278809. The next prime is 278819. The reversal of 278813 is 318872.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 158404 + 120409 = 398^2 + 347^2 .

It is a cyclic number.

It is not a de Polignac number, because 278813 - 2² = 278809 is a prime.

It is a Chen prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 278813.

It is not a weakly prime, because it can be changed into another prime (278819) by changing a digit.

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 as a sum of consecutive naturals, namely, 139406 + 139407.

It is an arithmetic number, because the mean of its divisors is an integer number (139407).

2²⁷⁸⁸¹³ is an apocalyptic number.

It is an amenable number.

278813 is a deficient number, since it is larger than the sum of its proper divisors (1).

278813 is an equidigital number, since it uses as much as digits as its factorization.

278813 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2688, while the sum is 29.

The square root of 278813 is about 528.0274614071. The cubic root of 278813 is about 65.3287486949.

Subtracting from 278813 its sum of digits (29), we obtain a square (278784 = 528²).

The spelling of 278813 in words is "two hundred seventy-eight thousand, eight hundred thirteen".