278806823 has 2 divisors, whose sum is σ = 278806824. Its totient is φ = 278806822.

The previous prime is 278806757. The next prime is 278806859. The reversal of 278806823 is 328608872.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 278806823 - 2¹⁰ = 278805799 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (278806123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 139403411 + 139403412.

It is an arithmetic number, because the mean of its divisors is an integer number (139403412).

Almost surely, 2^278806823 is an apocalyptic number.

278806823 is a deficient number, since it is larger than the sum of its proper divisors (1).

278806823 is an equidigital number, since it uses as much as digits as its factorization.

278806823 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 258048, while the sum is 44.

The square root of 278806823 is about 16697.5094849501. The cubic root of 278806823 is about 653.2826624650.

The spelling of 278806823 in words is "two hundred seventy-eight million, eight hundred six thousand, eight hundred twenty-three".