6438579840 has 640 divisors, whose sum is σ = 28684782720. Its totient is φ = 1337057280.

The previous prime is 6438579839. The next prime is 6438579863. The reversal of 6438579840 is 489758346.

6438579840 is a `hidden beast` number, since 64 + 3 + 8 + 579 + 8 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (640).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 3990874 + ... + 3992486.

It is an arithmetic number, because the mean of its divisors is an integer number (44819973).

Almost surely, 2^6438579840 is an apocalyptic number.

6438579840 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 6438579840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14342391360).

6438579840 is an abundant number, since it is smaller than the sum of its proper divisors (22246202880).

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

6438579840 is a wasteful number, since it uses less digits than its factorization.

6438579840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1662 (or 1641 counting only the distinct ones).

The product of its (nonzero) digits is 5806080, while the sum is 54.

The square root of 6438579840 is about 80240.7617112400. The cubic root of 6438579840 is about 1860.3587237353.

The spelling of 6438579840 in words is "six billion, four hundred thirty-eight million, five hundred seventy-nine thousand, eight hundred forty".