639934 has 4 divisors (see below), whose sum is σ = 959904. Its totient is φ = 319966.

The previous prime is 639911. The next prime is 639937. The reversal of 639934 is 439936.

It is a semiprime because it is the product of two primes.

It is a self number, because there is not a number n which added to its sum of digits gives 639934.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 159982 + ... + 159985.

It is an arithmetic number, because the mean of its divisors is an integer number (239976).

2⁶³⁹⁹³⁴ is an apocalyptic number.

639934 is a deficient number, since it is larger than the sum of its proper divisors (319970).

639934 is a wasteful number, since it uses less digits than its factorization.

639934 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 319969.

The product of its digits is 17496, while the sum is 34.

The square root of 639934 is about 799.9587489365. The cubic root of 639934 is about 86.1744251517.

The spelling of 639934 in words is "six hundred thirty-nine thousand, nine hundred thirty-four".