6643533660 has 96 divisors (see below), whose sum is σ = 19081101312. Its totient is φ = 1726302720.

The previous prime is 6643533599. The next prime is 6643533671. The reversal of 6643533660 is 663353466.

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 652005 + ... + 662115.

It is an arithmetic number, because the mean of its divisors is an integer number (198761472).

Almost surely, 2^6643533660 is an apocalyptic number.

6643533660 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 6643533660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9540550656).

6643533660 is an abundant number, since it is smaller than the sum of its proper divisors (12437567652).

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

6643533660 is a wasteful number, since it uses less digits than its factorization.

6643533660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10403 (or 10401 counting only the distinct ones).

The product of its (nonzero) digits is 699840, while the sum is 42.

The square root of 6643533660 is about 81507.8748342760. The cubic root of 6643533660 is about 1879.8926357127.

The spelling of 6643533660 in words is "six billion, six hundred forty-three million, five hundred thirty-three thousand, six hundred sixty".