6643875840 has 256 divisors, whose sum is σ = 24309815040. Its totient is φ = 1517813760.

The previous prime is 6643875839. The next prime is 6643875857. The reversal of 6643875840 is 485783466.

It is a tau number, because it is divible by the number of its divisors (256).

It is a zygodrome in base 2.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3439675 + ... + 3441605.

It is an arithmetic number, because the mean of its divisors is an integer number (94960215).

Almost surely, 2^6643875840 is an apocalyptic number.

6643875840 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 6643875840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12154907520).

6643875840 is an abundant number, since it is smaller than the sum of its proper divisors (17665939200).

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

6643875840 is an equidigital number, since it uses as much as digits as its factorization.

6643875840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1976 (or 1948 counting only the distinct ones).

The product of its (nonzero) digits is 3870720, while the sum is 51.

The square root of 6643875840 is about 81509.9738682328. The cubic root of 6643875840 is about 1879.9249102346.

The spelling of 6643875840 in words is "six billion, six hundred forty-three million, eight hundred seventy-five thousand, eight hundred forty".