6440680800 has 648 divisors, whose sum is σ = 25272210600. Its totient is φ = 1538887680.

The previous prime is 6440680783. The next prime is 6440680801. The reversal of 6440680800 is 80860446.

6440680800 is a `hidden beast` number, since 644 + 0 + 6 + 8 + 0 + 8 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6440680801) by changing a digit.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 72367156 + ... + 72367244.

It is an arithmetic number, because the mean of its divisors is an integer number (39000325).

Almost surely, 2^6440680800 is an apocalyptic number.

6440680800 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 6440680800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12636105300).

6440680800 is an abundant number, since it is smaller than the sum of its proper divisors (18831529800).

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

6440680800 is a wasteful number, since it uses less digits than its factorization.

6440680800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180 (or 141 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 36.

The square root of 6440680800 is about 80253.8522439889. The cubic root of 6440680800 is about 1860.5610516974.

The spelling of 6440680800 in words is "six billion, four hundred forty million, six hundred eighty thousand, eight hundred".