666736729 has 2 divisors, whose sum is σ = 666736730. Its totient is φ = 666736728.

The previous prime is 666736727. The next prime is 666736739. The reversal of 666736729 is 927637666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 578883600 + 87853129 = 24060^2 + 9373^2 .

It is a cyclic number.

It is not a de Polignac number, because 666736729 - 2¹ = 666736727 is a prime.

Together with 666736727, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (666736727) 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, 333368364 + 333368365.

It is an arithmetic number, because the mean of its divisors is an integer number (333368365).

Almost surely, 2^666736729 is an apocalyptic number.

It is an amenable number.

666736729 is a deficient number, since it is larger than the sum of its proper divisors (1).

666736729 is an equidigital number, since it uses as much as digits as its factorization.

666736729 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3429216, while the sum is 52.

The square root of 666736729 is about 25821.2456903225. The cubic root of 666736729 is about 873.6110662072.

The spelling of 666736729 in words is "six hundred sixty-six million, seven hundred thirty-six thousand, seven hundred twenty-nine".