6439643420 has 24 divisors (see below), whose sum is σ = 15455144544. Its totient is φ = 2207877696.

The previous prime is 6439643411. The next prime is 6439643437. The reversal of 6439643420 is 243469346.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22998587 + ... + 22998866.

It is an arithmetic number, because the mean of its divisors is an integer number (643964356).

Almost surely, 2^6439643420 is an apocalyptic number.

It is an amenable number.

6439643420 is an abundant number, since it is smaller than the sum of its proper divisors (9015501124).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6439643420 is a wasteful number, since it uses less digits than its factorization.

6439643420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45997469 (or 45997467 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 41.

The square root of 6439643420 is about 80247.3888671775. The cubic root of 6439643420 is about 1860.4611547807.

The spelling of 6439643420 in words is "six billion, four hundred thirty-nine million, six hundred forty-three thousand, four hundred twenty".