6399686400 has 432 divisors, whose sum is σ = 22719795840. Its totient is φ = 1581465600.

The previous prime is 6399686383. The next prime is 6399686413. The reversal of 6399686400 is 46869936.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 19334235 + ... + 19334565.

It is an arithmetic number, because the mean of its divisors is an integer number (52592120).

Almost surely, 2^6399686400 is an apocalyptic number.

6399686400 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6399686400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11359897920).

6399686400 is an abundant number, since it is smaller than the sum of its proper divisors (16320109440).

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

6399686400 is a wasteful number, since it uses less digits than its factorization.

6399686400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 432 (or 413 counting only the distinct ones).

The product of its (nonzero) digits is 1679616, while the sum is 51.

The square root of 6399686400 is about 79998.0399759894. The cubic root of 6399686400 is about 1856.6052079027.

The spelling of 6399686400 in words is "six billion, three hundred ninety-nine million, six hundred eighty-six thousand, four hundred".