639128 has 32 divisors (see below), whose sum is σ = 1395360. Its totient is φ = 268800.

The previous prime is 639091. The next prime is 639137. The reversal of 639128 is 821936.

It is a self number, because there is not a number n which added to its sum of digits gives 639128.

It is a congruent number.

It is an unprimeable number.

639128 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 7 ways as a sum of consecutive naturals, for example, 5600 + ... + 5712.

It is an arithmetic number, because the mean of its divisors is an integer number (43605).

2⁶³⁹¹²⁸ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (697680).

639128 is an abundant number, since it is smaller than the sum of its proper divisors (756232).

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

639128 is a wasteful number, since it uses less digits than its factorization.

639128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227 (or 223 counting only the distinct ones).

The product of its digits is 2592, while the sum is 29.

The square root of 639128 is about 799.4548142328. The cubic root of 639128 is about 86.1382309154.

It can be divided in two parts, 639 and 128, that added together give a palindrome (767).

The spelling of 639128 in words is "six hundred thirty-nine thousand, one hundred twenty-eight".