639505 has 8 divisors (see below), whose sum is σ = 777600. Its totient is φ = 504816.

The previous prime is 639493. The next prime is 639511. The reversal of 639505 is 505936.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 639505 - 2⁹ = 638993 is a prime.

639505 is a lucky number.

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 415 + ... + 1204.

It is an arithmetic number, because the mean of its divisors is an integer number (97200).

2⁶³⁹⁵⁰⁵ is an apocalyptic number.

It is an amenable number.

639505 is a deficient number, since it is larger than the sum of its proper divisors (138095).

639505 is a wasteful number, since it uses less digits than its factorization.

639505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1703.

The product of its (nonzero) digits is 4050, while the sum is 28.

The square root of 639505 is about 799.6905651563. The cubic root of 639505 is about 86.1551642631.

The spelling of 639505 in words is "six hundred thirty-nine thousand, five hundred five".