639834 has 24 divisors (see below), whose sum is σ = 1387872. Its totient is φ = 196560.

The previous prime is 639833. The next prime is 639839. The reversal of 639834 is 438936.

639834 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 639795 and 639804.

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

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 699 + ... + 1329.

It is an arithmetic number, because the mean of its divisors is an integer number (57828).

2⁶³⁹⁸³⁴ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639834, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (693936).

639834 is an abundant number, since it is smaller than the sum of its proper divisors (748038).

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

639834 is a wasteful number, since it uses less digits than its factorization.

639834 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 662 (or 649 counting only the distinct ones).

The product of its digits is 15552, while the sum is 33.

The square root of 639834 is about 799.8962432716. The cubic root of 639834 is about 86.1699362037.

The spelling of 639834 in words is "six hundred thirty-nine thousand, eight hundred thirty-four".