6643990660 has 48 divisors (see below), whose sum is σ = 14791351680. Its totient is φ = 2498178560.

The previous prime is 6643990631. The next prime is 6643990751. The reversal of 6643990660 is 660993466.

It is a happy number.

It is a super-2 number, since 2×6643990660² = 88285223780334471200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 273615 + ... + 296905.

It is an arithmetic number, because the mean of its divisors is an integer number (308153160).

Almost surely, 2^6643990660 is an apocalyptic number.

It is an amenable number.

6643990660 is an abundant number, since it is smaller than the sum of its proper divisors (8147361020).

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

6643990660 is a wasteful number, since it uses less digits than its factorization.

6643990660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24156 (or 24154 counting only the distinct ones).

The product of its (nonzero) digits is 1259712, while the sum is 49.

The square root of 6643990660 is about 81510.6781961726. The cubic root of 6643990660 is about 1879.9357398437.

The spelling of 6643990660 in words is "six billion, six hundred forty-three million, nine hundred ninety thousand, six hundred sixty".