6440213660 has 24 divisors (see below), whose sum is σ = 13533534000. Its totient is φ = 2574354944.

The previous prime is 6440213641. The next prime is 6440213669. The reversal of 6440213660 is 663120446.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6440213669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 77429 + ... + 137388.

It is an arithmetic number, because the mean of its divisors is an integer number (563897250).

Almost surely, 2^6440213660 is an apocalyptic number.

It is an amenable number.

6440213660 is an abundant number, since it is smaller than the sum of its proper divisors (7093320340).

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

6440213660 is a wasteful number, since it uses less digits than its factorization.

6440213660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216325 (or 216323 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 32.

The square root of 6440213660 is about 80250.9418013272. The cubic root of 6440213660 is about 1860.5160686937.

The spelling of 6440213660 in words is "six billion, four hundred forty million, two hundred thirteen thousand, six hundred sixty".