668512729 has 2 divisors, whose sum is σ = 668512730. Its totient is φ = 668512728.

The previous prime is 668512717. The next prime is 668512759. The reversal of 668512729 is 927215866.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 500551129 + 167961600 = 22373^2 + 12960^2 .

It is a cyclic number.

It is not a de Polignac number, because 668512729 - 2¹³ = 668504537 is a prime.

It is not a weakly prime, because it can be changed into another prime (668512759) 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, 334256364 + 334256365.

It is an arithmetic number, because the mean of its divisors is an integer number (334256365).

Almost surely, 2^668512729 is an apocalyptic number.

It is an amenable number.

668512729 is a deficient number, since it is larger than the sum of its proper divisors (1).

668512729 is an equidigital number, since it uses as much as digits as its factorization.

668512729 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 362880, while the sum is 46.

The square root of 668512729 is about 25855.6131043145. The cubic root of 668512729 is about 874.3860635959.

The spelling of 668512729 in words is "six hundred sixty-eight million, five hundred twelve thousand, seven hundred twenty-nine".