643518080 has 64 divisors (see below), whose sum is σ = 1542240000. Its totient is φ = 256766976.

The previous prime is 643518077. The next prime is 643518089. The reversal of 643518080 is 80815346.

It is a tau number, because it is divible by the number of its divisors (64).

It is a zygodrome in base 3.

It is a self number, because there is not a number n which added to its sum of digits gives 643518080.

It is not an unprimeable number, because it can be changed into a prime (643518089) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 320921 + ... + 322919.

It is an arithmetic number, because the mean of its divisors is an integer number (24097500).

Almost surely, 2^643518080 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643518080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (771120000).

643518080 is an abundant number, since it is smaller than the sum of its proper divisors (898721920).

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

643518080 is a wasteful number, since it uses less digits than its factorization.

643518080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2521 (or 2509 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 35.

The square root of 643518080 is about 25367.6581496992. The cubic root of 643518080 is about 863.3500484565.

The spelling of 643518080 in words is "six hundred forty-three million, five hundred eighteen thousand, eighty".