664445 has 8 divisors (see below), whose sum is σ = 844344. Its totient is φ = 500224.

The previous prime is 664441. The next prime is 664459. The reversal of 664445 is 544466.

It can be written as a sum of positive squares in 4 ways, for example, as 6724 + 657721 = 82^2 + 811^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 664445 - 2² = 664441 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3824 + ... + 3993.

It is an arithmetic number, because the mean of its divisors is an integer number (105543).

2⁶⁶⁴⁴⁴⁵ is an apocalyptic number.

It is an amenable number.

664445 is a deficient number, since it is larger than the sum of its proper divisors (179899).

664445 is a wasteful number, since it uses less digits than its factorization.

664445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7839.

The product of its digits is 11520, while the sum is 29.

The square root of 664445 is about 815.1349581511. The cubic root of 664445 is about 87.2608982481.

The spelling of 664445 in words is "six hundred sixty-four thousand, four hundred forty-five".