6439910399 has 4 divisors (see below), whose sum is σ = 6935288136. Its totient is φ = 5944532664.

The previous prime is 6439910381. The next prime is 6439910419. The reversal of 6439910399 is 9930199346.

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 6439910399 - 2²⁰ = 6438861823 is a prime.

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 6439910399.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6439910339) 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, 247688849 + ... + 247688874.

It is an arithmetic number, because the mean of its divisors is an integer number (1733822034).

Almost surely, 2^6439910399 is an apocalyptic number.

6439910399 is a deficient number, since it is larger than the sum of its proper divisors (495377737).

6439910399 is a wasteful number, since it uses less digits than its factorization.

6439910399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 495377736.

The product of its (nonzero) digits is 1417176, while the sum is 53.

The square root of 6439910399 is about 80249.0523246225. The cubic root of 6439910399 is about 1860.4868651688.

The spelling of 6439910399 in words is "six billion, four hundred thirty-nine million, nine hundred ten thousand, three hundred ninety-nine".