639028 has 12 divisors (see below), whose sum is σ = 1204420. Its totient is φ = 294912.

The previous prime is 639011. The next prime is 639043. The reversal of 639028 is 820936.

It can be written as a sum of positive squares in 2 ways, for example, as 300304 + 338724 = 548^2 + 582^2 .

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 638987 and 639005.

It is a congruent number.

It is an unprimeable number.

639028 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 (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6093 + ... + 6196.

2⁶³⁹⁰²⁸ is an apocalyptic number.

It is an amenable number.

639028 is a deficient number, since it is larger than the sum of its proper divisors (565392).

639028 is a wasteful number, since it uses less digits than its factorization.

639028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12306 (or 12304 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 639028 is about 799.3922691645. The cubic root of 639028 is about 86.1337381938.

The spelling of 639028 in words is "six hundred thirty-nine thousand, twenty-eight".