639023 has 16 divisors (see below), whose sum is σ = 819456. Its totient is φ = 483840.

The previous prime is 639011. The next prime is 639043. The reversal of 639023 is 320936.

It is a happy number.

It is not a de Polignac number, because 639023 - 2⁴ = 639007 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 639023.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639043) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3215 + ... + 3407.

It is an arithmetic number, because the mean of its divisors is an integer number (51216).

2⁶³⁹⁰²³ is an apocalyptic number.

639023 is a deficient number, since it is larger than the sum of its proper divisors (180433).

639023 is a wasteful number, since it uses less digits than its factorization.

639023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 254.

The product of its (nonzero) digits is 972, while the sum is 23.

The square root of 639023 is about 799.3891417826. The cubic root of 639023 is about 86.1335135454.

Adding to 639023 its reverse (320936), we get a palindrome (959959).

The spelling of 639023 in words is "six hundred thirty-nine thousand, twenty-three".