639423 has 12 divisors (see below), whose sum is σ = 964080. Its totient is φ = 407616.

The previous prime is 639391. The next prime is 639433. The reversal of 639423 is 324936.

639423 is a `hidden beast` number, since 639 + 4 + 23 = 666.

It is not a de Polignac number, because 639423 - 2⁵ = 639391 is a prime.

It is a d-powerful number, because it can be written as 6⁶ + 3³ + 4⁸ + 9³ + 2¹⁹ + 3⁷ .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639433) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1338 + ... + 1751.

It is an arithmetic number, because the mean of its divisors is an integer number (80340).

2⁶³⁹⁴²³ is an apocalyptic number.

639423 is a deficient number, since it is larger than the sum of its proper divisors (324657).

639423 is a wasteful number, since it uses less digits than its factorization.

639423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3118 (or 3115 counting only the distinct ones).

The product of its digits is 3888, while the sum is 27.

The square root of 639423 is about 799.6392936818. The cubic root of 639423 is about 86.1514817141.

The spelling of 639423 in words is "six hundred thirty-nine thousand, four hundred twenty-three".