6441640128 has 224 divisors, whose sum is σ = 23610539520. Its totient is φ = 1673118720.

The previous prime is 6441640103. The next prime is 6441640159. The reversal of 6441640128 is 8210461446.

It is a happy number.

6441640128 is a `hidden beast` number, since 6 + 4 + 4 + 1 + 640 + 1 + 2 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (224).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 6441640092 and 6441640101.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 108850 + ... + 157262.

Almost surely, 2^6441640128 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 6441640128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11805269760).

6441640128 is an abundant number, since it is smaller than the sum of its proper divisors (17168899392).

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

6441640128 is a wasteful number, since it uses less digits than its factorization.

6441640128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48452 (or 48436 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 36.

The square root of 6441640128 is about 80259.8288560348. The cubic root of 6441640128 is about 1860.6534228693.

The spelling of 6441640128 in words is "six billion, four hundred forty-one million, six hundred forty thousand, one hundred twenty-eight".