278726665601 has 2 divisors, whose sum is σ = 278726665602. Its totient is φ = 278726665600.

The previous prime is 278726665579. The next prime is 278726665603. The reversal of 278726665601 is 106566627872.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 278149705201 + 576960400 = 527399^2 + 24020^2 .

It is a cyclic number.

It is not a de Polignac number, because 278726665601 - 2⁶ = 278726665537 is a prime.

It is a Sophie Germain prime.

Together with 278726665603, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (278726665603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 139363332800 + 139363332801.

It is an arithmetic number, because the mean of its divisors is an integer number (139363332801).

Almost surely, 2^278726665601 is an apocalyptic number.

It is an amenable number.

278726665601 is a deficient number, since it is larger than the sum of its proper divisors (1).

278726665601 is an equidigital number, since it uses as much as digits as its factorization.

278726665601 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10160640, while the sum is 56.

The spelling of 278726665601 in words is "two hundred seventy-eight billion, seven hundred twenty-six million, six hundred sixty-five thousand, six hundred one".