6438320406 has 72 divisors (see below), whose sum is σ = 16241415840. Its totient is φ = 1837908576.

The previous prime is 6438320401. The next prime is 6438320417. The reversal of 6438320406 is 6040238346.

It is a happy number.

6438320406 is a `hidden beast` number, since 643 + 8 + 3 + 2 + 0 + 4 + 0 + 6 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6438320401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1309080 + ... + 1313988.

It is an arithmetic number, because the mean of its divisors is an integer number (225575220).

Almost surely, 2^6438320406 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6438320406, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8120707920).

6438320406 is an abundant number, since it is smaller than the sum of its proper divisors (9803095434).

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

6438320406 is a wasteful number, since it uses less digits than its factorization.

6438320406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6418 (or 6408 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 36.

The square root of 6438320406 is about 80239.1450976392. The cubic root of 6438320406 is about 1860.3337365073. Note that the first 3 decimals are identical.

The spelling of 6438320406 in words is "six billion, four hundred thirty-eight million, three hundred twenty thousand, four hundred six".