664673 has 4 divisors (see below), whose sum is σ = 677268. Its totient is φ = 652080.

The previous prime is 664669. The next prime is 664679. The reversal of 664673 is 376466.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 529984 + 134689 = 728^2 + 367^2 .

It is a cyclic number.

It is not a de Polignac number, because 664673 - 2² = 664669 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (664679) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6218 + ... + 6323.

It is an arithmetic number, because the mean of its divisors is an integer number (169317).

2⁶⁶⁴⁶⁷³ is an apocalyptic number.

It is an amenable number.

664673 is a deficient number, since it is larger than the sum of its proper divisors (12595).

664673 is a wasteful number, since it uses less digits than its factorization.

664673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12594.

The product of its digits is 18144, while the sum is 32.

The square root of 664673 is about 815.2748002974. The cubic root of 664673 is about 87.2708781108.

The spelling of 664673 in words is "six hundred sixty-four thousand, six hundred seventy-three".