668009 has 2 divisors, whose sum is σ = 668010. Its totient is φ = 668008.

The previous prime is 667999. The next prime is 668029. The reversal of 668009 is 900866.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 547600 + 120409 = 740^2 + 347^2 .

It is a cyclic number.

It is not a de Polignac number, because 668009 - 2⁸ = 667753 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (668029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334004 + 334005.

It is an arithmetic number, because the mean of its divisors is an integer number (334005).

2⁶⁶⁸⁰⁰⁹ is an apocalyptic number.

It is an amenable number.

668009 is a deficient number, since it is larger than the sum of its proper divisors (1).

668009 is an equidigital number, since it uses as much as digits as its factorization.

668009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 668009 is about 817.3181754984. The cubic root of 668009 is about 87.4166389747.

The spelling of 668009 in words is "six hundred sixty-eight thousand, nine".