278891 has 2 divisors, whose sum is σ = 278892. Its totient is φ = 278890.

The previous prime is 278881. The next prime is 278903. The reversal of 278891 is 198872.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 278891 - 2⁶ = 278827 is a prime.

It is not a weakly prime, because it can be changed into another prime (278801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 139445 + 139446.

It is an arithmetic number, because the mean of its divisors is an integer number (139446).

2²⁷⁸⁸⁹¹ is an apocalyptic number.

278891 is a deficient number, since it is larger than the sum of its proper divisors (1).

278891 is an equidigital number, since it uses as much as digits as its factorization.

278891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8064, while the sum is 35.

The square root of 278891 is about 528.1013160370. The cubic root of 278891 is about 65.3348401939.

The spelling of 278891 in words is "two hundred seventy-eight thousand, eight hundred ninety-one".