639328 has 12 divisors (see below), whose sum is σ = 1258740. Its totient is φ = 319648.

The previous prime is 639311. The next prime is 639329. The reversal of 639328 is 823936.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 639328.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639329) by changing a digit.

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 as a sum of consecutive naturals, namely, 9958 + ... + 10021.

It is an arithmetic number, because the mean of its divisors is an integer number (104895).

2⁶³⁹³²⁸ is an apocalyptic number.

It is an amenable number.

639328 is a deficient number, since it is larger than the sum of its proper divisors (619412).

639328 is a wasteful number, since it uses less digits than its factorization.

639328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19989 (or 19981 counting only the distinct ones).

The product of its digits is 7776, while the sum is 31.

The square root of 639328 is about 799.5798896921. The cubic root of 639328 is about 86.1472149527.

The spelling of 639328 in words is "six hundred thirty-nine thousand, three hundred twenty-eight".