6399643008 has 128 divisors (see below), whose sum is σ = 18592560000. Its totient is φ = 1934254080.

The previous prime is 6399642971. The next prime is 6399643021. The reversal of 6399643008 is 8003469936.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1827243 + ... + 1830741.

It is an arithmetic number, because the mean of its divisors is an integer number (145254375).

Almost surely, 2^6399643008 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6399643008, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9296280000).

6399643008 is an abundant number, since it is smaller than the sum of its proper divisors (12192916992).

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

6399643008 is a wasteful number, since it uses less digits than its factorization.

6399643008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3960 (or 3948 counting only the distinct ones).

The product of its (nonzero) digits is 839808, while the sum is 48.

The square root of 6399643008 is about 79997.7687688850. The cubic root of 6399643008 is about 1856.6010117599.

The spelling of 6399643008 in words is "six billion, three hundred ninety-nine million, six hundred forty-three thousand, eight".