6643540 has 24 divisors (see below), whose sum is σ = 14686560. Its totient is φ = 2517408.

The previous prime is 6643537. The next prime is 6643589. The reversal of 6643540 is 453466.

It is a junction number, because it is equal to n+sod(n) for n = 6643499 and 6643508.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 8362 + ... + 9121.

It is an arithmetic number, because the mean of its divisors is an integer number (611940).

Almost surely, 2^6643540 is an apocalyptic number.

It is an amenable number.

6643540 is an abundant number, since it is smaller than the sum of its proper divisors (8043020).

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

6643540 is a wasteful number, since it uses less digits than its factorization.

6643540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17511 (or 17509 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 28.

The square root of 6643540 is about 2577.5065470334. The cubic root of 6643540 is about 187.9893233713.

The spelling of 6643540 in words is "six million, six hundred forty-three thousand, five hundred forty".