639005 has 8 divisors (see below), whose sum is σ = 771552. Its totient is φ = 508048.

The previous prime is 638999. The next prime is 639007. The reversal of 639005 is 500936.

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 639005 - 2¹⁴ = 622621 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639007) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 854 + ... + 1416.

It is an arithmetic number, because the mean of its divisors is an integer number (96444).

2⁶³⁹⁰⁰⁵ is an apocalyptic number.

It is an amenable number.

639005 is a deficient number, since it is larger than the sum of its proper divisors (132547).

639005 is a wasteful number, since it uses less digits than its factorization.

639005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 795.

The product of its (nonzero) digits is 810, while the sum is 23.

The square root of 639005 is about 799.3778831066. The cubic root of 639005 is about 86.1327048016.

The spelling of 639005 in words is "six hundred thirty-nine thousand, five".