408639 has 32 divisors (see below), whose sum is σ = 714240. Its totient is φ = 201600.

The previous prime is 408637. The next prime is 408643. The reversal of 408639 is 936804.

It is not a de Polignac number, because 408639 - 2¹ = 408637 is a prime.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

408639 is a lucky number.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (408631) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6669 + ... + 6729.

It is an arithmetic number, because the mean of its divisors is an integer number (22320).

2⁴⁰⁸⁶³⁹ is an apocalyptic number.

408639 is a deficient number, since it is larger than the sum of its proper divisors (305601).

408639 is a wasteful number, since it uses less digits than its factorization.

408639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111.

The product of its (nonzero) digits is 5184, while the sum is 30.

The square root of 408639 is about 639.2487778635. The cubic root of 408639 is about 74.2072955582.

The spelling of 408639 in words is "four hundred eight thousand, six hundred thirty-nine".