664320 has 72 divisors (see below), whose sum is σ = 2133936. Its totient is φ = 176128.

The previous prime is 664319. The next prime is 664331. The reversal of 664320 is 23466.

It is a hoax number, since the sum of its digits (21) coincides with the sum of the digits of its distinct prime factors.

It is a nialpdrome in base 10.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 664320.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3754 + ... + 3926.

It is an arithmetic number, because the mean of its divisors is an integer number (29638).

2⁶⁶⁴³²⁰ is an apocalyptic number.

664320 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 664320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1066968).

664320 is an abundant number, since it is smaller than the sum of its proper divisors (1469616).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

664320 is a wasteful number, since it uses less digits than its factorization.

664320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197 (or 183 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 21.

The square root of 664320 is about 815.0582801248. The cubic root of 664320 is about 87.2554258632.

Adding to 664320 its reverse (23466), we get a palindrome (687786).

The spelling of 664320 in words is "six hundred sixty-four thousand, three hundred twenty".