6643543500 has 144 divisors (see below), whose sum is σ = 22863623328. Its totient is φ = 1610544000.

The previous prime is 6643543471. The next prime is 6643543507. The reversal of 6643543500 is 53453466.

6643543500 is a `hidden beast` number, since 6 + 64 + 3 + 543 + 50 + 0 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (6643543507) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 17607 + ... + 116606.

It is an arithmetic number, because the mean of its divisors is an integer number (158775162).

Almost surely, 2^6643543500 is an apocalyptic number.

6643543500 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 6643543500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11431811664).

6643543500 is an abundant number, since it is smaller than the sum of its proper divisors (16220079828).

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

6643543500 is a wasteful number, since it uses less digits than its factorization.

6643543500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134249 (or 134234 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 36.

The square root of 6643543500 is about 81507.9351965194. The cubic root of 6643543500 is about 1879.8935638399.

Adding to 6643543500 its reverse (53453466), we get a palindrome (6696996966).

The spelling of 6643543500 in words is "six billion, six hundred forty-three million, five hundred forty-three thousand, five hundred".