6404639808 has 112 divisors (see below), whose sum is σ = 19410297984. Its totient is φ = 1825751040.

The previous prime is 6404639749. The next prime is 6404639831. The reversal of 6404639808 is 8089364046.

It is a tau number, because it is divible by the number of its divisors (112).

It is a super-2 number, since 2×6404639808² = 82038822140436553728, which contains 22 as substring.

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

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, 614416 + ... + 624752.

It is an arithmetic number, because the mean of its divisors is an integer number (173306232).

Almost surely, 2^6404639808 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 6404639808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9705148992).

6404639808 is an abundant number, since it is smaller than the sum of its proper divisors (13005658176).

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

6404639808 is a wasteful number, since it uses less digits than its factorization.

6404639808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10820 (or 10810 counting only the distinct ones).

The product of its (nonzero) digits is 995328, while the sum is 48.

The square root of 6404639808 is about 80028.9935460893. The cubic root of 6404639808 is about 1857.0840934193.

The spelling of 6404639808 in words is "six billion, four hundred four million, six hundred thirty-nine thousand, eight hundred eight".