639321 has 8 divisors (see below), whose sum is σ = 861120. Its totient is φ = 421872.

The previous prime is 639311. The next prime is 639329. The reversal of 639321 is 123936.

639321 is digitally balanced in base 7, 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 639321 - 2⁶ = 639257 is a prime.

It is a Smith number, since the sum of its digits (24) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

639321 is strictly pandigital in base 7.

It is a nialpdrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 639291 and 639300.

It is not an unprimeable number, because it can be changed into a prime (639329) 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, 726 + ... + 1343.

It is an arithmetic number, because the mean of its divisors is an integer number (107640).

2⁶³⁹³²¹ is an apocalyptic number.

It is an amenable number.

639321 is a deficient number, since it is larger than the sum of its proper divisors (221799).

639321 is a wasteful number, since it uses less digits than its factorization.

639321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2175.

The product of its digits is 972, while the sum is 24.

The square root of 639321 is about 799.5755123814. The cubic root of 639321 is about 86.1469005431.

The spelling of 639321 in words is "six hundred thirty-nine thousand, three hundred twenty-one".