6621439 has 4 divisors (see below), whose sum is σ = 7223400. Its totient is φ = 6019480.

The previous prime is 6621421. The next prime is 6621451. The reversal of 6621439 is 9341266.

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 6621439 - 2⁷ = 6621311 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 6621439.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6621499) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 300964 + ... + 300985.

It is an arithmetic number, because the mean of its divisors is an integer number (1805850).

Almost surely, 2^6621439 is an apocalyptic number.

6621439 is a deficient number, since it is larger than the sum of its proper divisors (601961).

6621439 is a wasteful number, since it uses less digits than its factorization.

6621439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 601960.

The product of its digits is 7776, while the sum is 31.

The square root of 6621439 is about 2573.2156924751. The cubic root of 6621439 is about 187.7806310296.

The spelling of 6621439 in words is "six million, six hundred twenty-one thousand, four hundred thirty-nine".