664646 has 8 divisors (see below), whose sum is σ = 1000560. Its totient is φ = 331128.

The previous prime is 664633. The next prime is 664661. The reversal of 664646 is 646466.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

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, 500 + ... + 1256.

It is an arithmetic number, because the mean of its divisors is an integer number (125070).

2⁶⁶⁴⁶⁴⁶ is an apocalyptic number.

664646 is a deficient number, since it is larger than the sum of its proper divisors (335914).

664646 is a wasteful number, since it uses less digits than its factorization.

664646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1198.

The product of its digits is 20736, while the sum is 32.

The square root of 664646 is about 815.2582412954. The cubic root of 664646 is about 87.2696964041.

The spelling of 664646 in words is "six hundred sixty-four thousand, six hundred forty-six".