6440544000 has 864 divisors, whose sum is σ = 26861103360. Its totient is φ = 1465344000.

The previous prime is 6440543969. The next prime is 6440544001. The reversal of 6440544000 is 4450446.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6440544001) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 60191947 + ... + 60192053.

It is an arithmetic number, because the mean of its divisors is an integer number (31089240).

Almost surely, 2^6440544000 is an apocalyptic number.

6440544000 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 6440544000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13430551680).

6440544000 is an abundant number, since it is smaller than the sum of its proper divisors (20420559360).

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

6440544000 is a wasteful number, since it uses less digits than its factorization.

6440544000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174 (or 147 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 27.

The square root of 6440544000 is about 80252.9999439273. Note that the first 4 decimals coincide. The cubic root of 6440544000 is about 1860.5478788376.

Adding to 6440544000 its reverse (4450446), we get a palindrome (6444994446).

The spelling of 6440544000 in words is "six billion, four hundred forty million, five hundred forty-four thousand".