6531128664 has 128 divisors (see below), whose sum is σ = 16919020800. Its totient is φ = 2100101120.

The previous prime is 6531128641. The next prime is 6531128677. The reversal of 6531128664 is 4668211356.

It is a congruent number.

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, 25412824 + ... + 25413080.

It is an arithmetic number, because the mean of its divisors is an integer number (132179850).

Almost surely, 2^6531128664 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 6531128664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8459510400).

6531128664 is an abundant number, since it is smaller than the sum of its proper divisors (10387892136).

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

6531128664 is a wasteful number, since it uses less digits than its factorization.

6531128664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 593 (or 589 counting only the distinct ones).

The product of its digits is 207360, while the sum is 42.

The square root of 6531128664 is about 80815.3986811919. The cubic root of 6531128664 is about 1869.2300169134.

The spelling of 6531128664 in words is "six billion, five hundred thirty-one million, one hundred twenty-eight thousand, six hundred sixty-four".