639673 has 8 divisors (see below), whose sum is σ = 681120. Its totient is φ = 599040.

The previous prime is 639671. The next prime is 639677. The reversal of 639673 is 376936.

639673 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 639673 - 2¹ = 639671 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639671) 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, 2361 + ... + 2617.

It is an arithmetic number, because the mean of its divisors is an integer number (85140).

2⁶³⁹⁶⁷³ is an apocalyptic number.

It is an amenable number.

639673 is a deficient number, since it is larger than the sum of its proper divisors (41447).

639673 is a wasteful number, since it uses less digits than its factorization.

639673 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407.

The product of its digits is 20412, while the sum is 34.

The square root of 639673 is about 799.7955988876. The cubic root of 639673 is about 86.1627080145.

The spelling of 639673 in words is "six hundred thirty-nine thousand, six hundred seventy-three".