668448779 has 2 divisors, whose sum is σ = 668448780. Its totient is φ = 668448778.

The previous prime is 668448727. The next prime is 668448787. The reversal of 668448779 is 977844866.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-668448779 is a prime.

It is not a weakly prime, because it can be changed into another prime (668444779) 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, 334224389 + 334224390.

It is an arithmetic number, because the mean of its divisors is an integer number (334224390).

Almost surely, 2^668448779 is an apocalyptic number.

668448779 is a deficient number, since it is larger than the sum of its proper divisors (1).

668448779 is an equidigital number, since it uses as much as digits as its factorization.

668448779 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16257024, while the sum is 59.

The square root of 668448779 is about 25854.3763993642. The cubic root of 668448779 is about 874.3581814183.

The spelling of 668448779 in words is "six hundred sixty-eight million, four hundred forty-eight thousand, seven hundred seventy-nine".