639494 has 4 divisors (see below), whose sum is σ = 959244. Its totient is φ = 319746.

The previous prime is 639493. The next prime is 639511. The reversal of 639494 is 494936.

It is a happy number.

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

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 639494.

It is not an unprimeable number, because it can be changed into a prime (639491) 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, 159872 + ... + 159875.

It is an arithmetic number, because the mean of its divisors is an integer number (239811).

2⁶³⁹⁴⁹⁴ is an apocalyptic number.

639494 is a deficient number, since it is larger than the sum of its proper divisors (319750).

639494 is a wasteful number, since it uses less digits than its factorization.

639494 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 319749.

The product of its digits is 23328, while the sum is 35.

The square root of 639494 is about 799.6836874665. The cubic root of 639494 is about 86.1546702809.

The spelling of 639494 in words is "six hundred thirty-nine thousand, four hundred ninety-four".