6440003640 has 192 divisors, whose sum is σ = 25179148800. Its totient is φ = 1394516736.

The previous prime is 6440003617. The next prime is 6440003641. The reversal of 6440003640 is 463000446.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6440003641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 19372 + ... + 115131.

It is an arithmetic number, because the mean of its divisors is an integer number (131141400).

Almost surely, 2^6440003640 is an apocalyptic number.

6440003640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6440003640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12589574400).

6440003640 is an abundant number, since it is smaller than the sum of its proper divisors (18739145160).

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

6440003640 is a wasteful number, since it uses less digits than its factorization.

6440003640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134546 (or 134539 counting only the distinct ones).

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

The square root of 6440003640 is about 80249.6332701901. The cubic root of 6440003640 is about 1860.4958442181.

The spelling of 6440003640 in words is "six billion, four hundred forty million, three thousand, six hundred forty".