6643440 has 60 divisors (see below), whose sum is σ = 22313304. Its totient is φ = 1771392.

The previous prime is 6643423. The next prime is 6643453. The reversal of 6643440 is 443466.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (60).

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 11 ways as a sum of consecutive naturals, for example, 3894 + ... + 5333.

Almost surely, 2^6643440 is an apocalyptic number.

6643440 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

6643440 is an abundant number, since it is smaller than the sum of its proper divisors (15669864).

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

6643440 is a wasteful number, since it uses less digits than its factorization.

6643440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9246 (or 9237 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 27.

The square root of 6643440 is about 2577.4871483676. The cubic root of 6643440 is about 187.9883801480.

The spelling of 6643440 in words is "six million, six hundred forty-three thousand, four hundred forty".