278438243 has 2 divisors, whose sum is σ = 278438244. Its totient is φ = 278438242.

The previous prime is 278438233. The next prime is 278438261. The reversal of 278438243 is 342834872.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 278438243 - 2²⁰ = 277389667 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 278438243.

It is not a weakly prime, because it can be changed into another prime (278438233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 139219121 + 139219122.

It is an arithmetic number, because the mean of its divisors is an integer number (139219122).

Almost surely, 2^278438243 is an apocalyptic number.

278438243 is a deficient number, since it is larger than the sum of its proper divisors (1).

278438243 is an equidigital number, since it uses as much as digits as its factorization.

278438243 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 258048, while the sum is 41.

The square root of 278438243 is about 16686.4688595281. The cubic root of 278438243 is about 652.9946576676.

The spelling of 278438243 in words is "two hundred seventy-eight million, four hundred thirty-eight thousand, two hundred forty-three".