6400000000 has 135 divisors (see below), whose sum is σ = 15999503527. Its totient is φ = 2560000000.

The previous prime is 6399999959. The next prime is 6400000007. The reversal of 6400000000 is 46.

The square root of 6400000000 is 80000.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 4550311936 + 1849688064 = 67456^2 + 43008^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=4, B=200.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a Duffinian number.

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (6400000007) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1279999998 + ... + 1280000002.

Almost surely, 2^6400000000 is an apocalyptic number.

6400000000 is the 80000-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6400000000

6400000000 is an abundant number, since it is smaller than the sum of its proper divisors (9599503527).

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

6400000000 is an frugal number, since it uses more digits than its factorization.

6400000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68 (or 7 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 10.

The cubic root of 6400000000 is about 1856.6355334451.

Multiplying 6400000000 by its sum of digits (10), we get a cube (64000000000 = 4000³).

Adding to 6400000000 its reverse (46), we get a palindrome (6400000046).

The spelling of 6400000000 in words is "six billion, four hundred million", and thus it is an aban number.