668776673 has 2 divisors, whose sum is σ = 668776674. Its totient is φ = 668776672.

The previous prime is 668776663. The next prime is 668776679. The reversal of 668776673 is 376677866.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 572501329 + 96275344 = 23927^2 + 9812^2 .

It is a cyclic number.

It is not a de Polignac number, because 668776673 - 2⁴ = 668776657 is a prime.

It is a super-3 number, since 3×668776673³ (a number of 27 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (668776679) 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, 334388336 + 334388337.

It is an arithmetic number, because the mean of its divisors is an integer number (334388337).

Almost surely, 2^668776673 is an apocalyptic number.

It is an amenable number.

668776673 is a deficient number, since it is larger than the sum of its proper divisors (1).

668776673 is an equidigital number, since it uses as much as digits as its factorization.

668776673 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10668672, while the sum is 56.

The square root of 668776673 is about 25860.7167920767. The cubic root of 668776673 is about 874.5011242763.

The spelling of 668776673 in words is "six hundred sixty-eight million, seven hundred seventy-six thousand, six hundred seventy-three".