664717 has 8 divisors (see below), whose sum is σ = 716472. Its totient is φ = 614400.

The previous prime is 664711. The next prime is 664739. The reversal of 664717 is 717466.

It can be written as a sum of positive squares in 4 ways, for example, as 137641 + 527076 = 371^2 + 726^2 .

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 664717 - 2⁷ = 664589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664711) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 717 + ... + 1357.

It is an arithmetic number, because the mean of its divisors is an integer number (89559).

2⁶⁶⁴⁷¹⁷ is an apocalyptic number.

It is an amenable number.

664717 is a deficient number, since it is larger than the sum of its proper divisors (51755).

664717 is a wasteful number, since it uses less digits than its factorization.

664717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 719.

The product of its digits is 7056, while the sum is 31.

The square root of 664717 is about 815.3017846172. The cubic root of 664717 is about 87.2728037865.

The spelling of 664717 in words is "six hundred sixty-four thousand, seven hundred seventeen".