668439 has 16 divisors (see below), whose sum is σ = 1043200. Its totient is φ = 421848.

The previous prime is 668417. The next prime is 668471. The reversal of 668439 is 934866.

668439 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 668439 - 2⁵ = 668407 is a prime.

It is a Duffinian number.

668439 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668539) 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, 139 + ... + 1164.

It is an arithmetic number, because the mean of its divisors is an integer number (65200).

2⁶⁶⁸⁴³⁹ is an apocalyptic number.

668439 is a deficient number, since it is larger than the sum of its proper divisors (374761).

668439 is a wasteful number, since it uses less digits than its factorization.

668439 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1331 (or 1325 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 668439 is about 817.5811886290. The cubic root of 668439 is about 87.4353917621.

The spelling of 668439 in words is "six hundred sixty-eight thousand, four hundred thirty-nine".