1408639 has 4 divisors (see below), whose sum is σ = 1411056. Its totient is φ = 1406224.

The previous prime is 1408633. The next prime is 1408651. The reversal of 1408639 is 9368041.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1408639 - 2¹¹ = 1406591 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1408639.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1408633) 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, 267 + ... + 1699.

It is an arithmetic number, because the mean of its divisors is an integer number (352764).

2^1408639 is an apocalyptic number.

1408639 is a deficient number, since it is larger than the sum of its proper divisors (2417).

1408639 is an equidigital number, since it uses as much as digits as its factorization.

1408639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2416.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 1408639 is about 1186.8609859626. The cubic root of 1408639 is about 112.0985261839.

The spelling of 1408639 in words is "one million, four hundred eight thousand, six hundred thirty-nine".