6643530 has 48 divisors (see below), whose sum is σ = 17474184. Its totient is φ = 1751040.

The previous prime is 6643513. The next prime is 6643537. The reversal of 6643530 is 353466.

It can be written as a sum of positive squares in 4 ways, for example, as 2852721 + 3790809 = 1689^2 + 1947^2 .

It is a junction number, because it is equal to n+sod(n) for n = 6643494 and 6643503.

It is not an unprimeable number, because it can be changed into a prime (6643537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8350 + ... + 9110.

Almost surely, 2^6643530 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6643530, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8737092).

6643530 is an abundant number, since it is smaller than the sum of its proper divisors (10830654).

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

6643530 is a wasteful number, since it uses less digits than its factorization.

6643530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 871 (or 868 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 27.

The square root of 6643530 is about 2577.5046071734. The cubic root of 6643530 is about 187.9892290494.

Adding to 6643530 its reverse (353466), we get a palindrome (6996996).

Subtracting from 6643530 its reverse (353466), we obtain a square (6290064 = 2508²).

The spelling of 6643530 in words is "six million, six hundred forty-three thousand, five hundred thirty".