664917 has 8 divisors (see below), whose sum is σ = 967200. Its totient is φ = 402960.

The previous prime is 664891. The next prime is 664933. The reversal of 664917 is 719466.

It is a happy number.

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

It is not a de Polignac number, because 664917 - 2⁷ = 664789 is a prime.

It is a super-2 number, since 2×664917² = 884229233778, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 20149 = 664917 / (6 + 6 + 4 + 9 + 1 + 7).

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 664917.

It is not an unprimeable number, because it can be changed into a prime (664967) 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, 10042 + ... + 10107.

It is an arithmetic number, because the mean of its divisors is an integer number (120900).

2⁶⁶⁴⁹¹⁷ is an apocalyptic number.

It is an amenable number.

664917 is a deficient number, since it is larger than the sum of its proper divisors (302283).

664917 is a wasteful number, since it uses less digits than its factorization.

664917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20163.

The product of its digits is 9072, while the sum is 33.

The square root of 664917 is about 815.4244293618. The cubic root of 664917 is about 87.2815557870.

It can be divided in two parts, 6649 and 17, that added together give a palindrome (6666).

The spelling of 664917 in words is "six hundred sixty-four thousand, nine hundred seventeen".