663321 has 8 divisors (see below), whose sum is σ = 891904. Its totient is φ = 438480.

The previous prime is 663319. The next prime is 663331. The reversal of 663321 is 123366.

663321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 663321 - 2¹ = 663319 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (663301) 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, 490 + ... + 1251.

It is an arithmetic number, because the mean of its divisors is an integer number (111488).

2⁶⁶³³²¹ is an apocalyptic number.

It is an amenable number.

663321 is a deficient number, since it is larger than the sum of its proper divisors (228583).

663321 is a wasteful number, since it uses less digits than its factorization.

663321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1871.

The product of its digits is 648, while the sum is 21.

The square root of 663321 is about 814.4452099436. The cubic root of 663321 is about 87.2116658774.

Adding to 663321 its reverse (123366), we get a palindrome (786687).

The spelling of 663321 in words is "six hundred sixty-three thousand, three hundred twenty-one".