6400398816 has 288 divisors, whose sum is σ = 22995614880. Its totient is φ = 1720922112.

The previous prime is 6400398791. The next prime is 6400398817. The reversal of 6400398816 is 6188930046.

It is a tau number, because it is divible by the number of its divisors (288).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6400398817) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 715266 + ... + 724158.

It is an arithmetic number, because the mean of its divisors is an integer number (79845885).

Almost surely, 2^6400398816 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 6400398816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11497807440).

6400398816 is an abundant number, since it is smaller than the sum of its proper divisors (16595216064).

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

6400398816 is a wasteful number, since it uses less digits than its factorization.

6400398816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8943 (or 8922 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The square root of 6400398816 is about 80002.4925611696. The cubic root of 6400398816 is about 1856.6740980585.

The spelling of 6400398816 in words is "six billion, four hundred million, three hundred ninety-eight thousand, eight hundred sixteen".