639832 has 8 divisors (see below), whose sum is σ = 1199700. Its totient is φ = 319912.

The previous prime is 639757. The next prime is 639833. The reversal of 639832 is 238936.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 639794 and 639803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639833) by changing a digit.

639832 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39982 + ... + 39997.

2⁶³⁹⁸³² is an apocalyptic number.

It is an amenable number.

639832 is a deficient number, since it is larger than the sum of its proper divisors (559868).

639832 is a wasteful number, since it uses less digits than its factorization.

639832 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79985 (or 79981 counting only the distinct ones).

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

The square root of 639832 is about 799.8949931085. The cubic root of 639832 is about 86.1698464200.

The spelling of 639832 in words is "six hundred thirty-nine thousand, eight hundred thirty-two".