664679 has 2 divisors, whose sum is σ = 664680. Its totient is φ = 664678.

The previous prime is 664669. The next prime is 664687. The reversal of 664679 is 976466.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 664679 - 2⁴ = 664663 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332339 + 332340.

It is an arithmetic number, because the mean of its divisors is an integer number (332340).

2⁶⁶⁴⁶⁷⁹ is an apocalyptic number.

664679 is a deficient number, since it is larger than the sum of its proper divisors (1).

664679 is an equidigital number, since it uses as much as digits as its factorization.

664679 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 54432, while the sum is 38.

The square root of 664679 is about 815.2784800300. The cubic root of 664679 is about 87.2711407080.

The spelling of 664679 in words is "six hundred sixty-four thousand, six hundred seventy-nine".