639173 has 4 divisors (see below), whose sum is σ = 641088. Its totient is φ = 637260.

The previous prime is 639169. The next prime is 639181. The reversal of 639173 is 371936.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 639173 - 2² = 639169 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 (639143) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 311 + ... + 1172.

It is an arithmetic number, because the mean of its divisors is an integer number (160272).

2⁶³⁹¹⁷³ is an apocalyptic number.

It is an amenable number.

639173 is a deficient number, since it is larger than the sum of its proper divisors (1915).

639173 is a wasteful number, since it uses less digits than its factorization.

639173 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1914.

The product of its digits is 3402, while the sum is 29.

The square root of 639173 is about 799.4829579172. The cubic root of 639173 is about 86.1402524872.

The spelling of 639173 in words is "six hundred thirty-nine thousand, one hundred seventy-three".