6640807680 has 540 divisors, whose sum is σ = 25798366440. Its totient is φ = 1630347264.

The previous prime is 6640807637. The next prime is 6640807697. The reversal of 6640807680 is 867080466.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (540).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 17521731 + ... + 17522109.

Almost surely, 2^6640807680 is an apocalyptic number.

6640807680 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 6640807680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12899183220).

6640807680 is an abundant number, since it is smaller than the sum of its proper divisors (19157558760).

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

6640807680 is a wasteful number, since it uses less digits than its factorization.

6640807680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 438 (or 402 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 45.

The square root of 6640807680 is about 81491.1509306379. The cubic root of 6640807680 is about 1879.6354808584.

The spelling of 6640807680 in words is "six billion, six hundred forty million, eight hundred seven thousand, six hundred eighty".