6399991926 has 40 divisors (see below), whose sum is σ = 14369415984. Its totient is φ = 2129062320.

The previous prime is 6399991879. The next prime is 6399991967. The reversal of 6399991926 is 6291999936.

It is a nude number because it is divisible by every one of its digits.

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 19 ways as a sum of consecutive naturals, for example, 42216 + ... + 120756.

Almost surely, 2^6399991926 is an apocalyptic number.

6399991926 is an abundant number, since it is smaller than the sum of its proper divisors (7969424058).

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

6399991926 is a wasteful number, since it uses less digits than its factorization.

6399991926 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79058 (or 79049 counting only the distinct ones).

The product of its digits is 12754584, while the sum is 63.

The square root of 6399991926 is about 79999.9495374841. The cubic root of 6399991926 is about 1856.6347526909.

The spelling of 6399991926 in words is "six billion, three hundred ninety-nine million, nine hundred ninety-one thousand, nine hundred twenty-six".