639104 has 16 divisors (see below), whose sum is σ = 1273470. Its totient is φ = 319488.

The previous prime is 639091. The next prime is 639137. The reversal of 639104 is 401936.

It can be written as a sum of positive squares in only one way, i.e., 577600 + 61504 = 760^2 + 248^2 .

It is a tau number, because it is divible by the number of its divisors (16).

It is a self number, because there is not a number n which added to its sum of digits gives 639104.

It is a congruent number.

It is an unprimeable number.

639104 is an untouchable number, because it is not equal to the sum of proper divisors of any 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 as a sum of consecutive naturals, namely, 2369 + ... + 2624.

2⁶³⁹¹⁰⁴ is an apocalyptic number.

639104 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

639104 is a deficient number, since it is larger than the sum of its proper divisors (634366).

639104 is an equidigital number, since it uses as much as digits as its factorization.

639104 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5007 (or 4995 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 23.

The square root of 639104 is about 799.4398038627. The cubic root of 639104 is about 86.1371527049.

The spelling of 639104 in words is "six hundred thirty-nine thousand, one hundred four".