643881100608 has 168 divisors, whose sum is σ = 1893689801640. Its totient is φ = 209048125440.

The previous prime is 643881100571. The next prime is 643881100661. The reversal of 643881100608 is 806001188346.

It is a happy number.

643881100608 is a `hidden beast` number, since 6 + 4 + 38 + 8 + 1 + 1 + 0 + 0 + 608 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 173329003584 + 470552097024 = 416328^2 + 685968^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14548978 + ... + 14593166.

It is an arithmetic number, because the mean of its divisors is an integer number (11271963105).

Almost surely, 2^643881100608 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 643881100608, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (946844900820).

643881100608 is an abundant number, since it is smaller than the sum of its proper divisors (1249808701032).

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

643881100608 is a wasteful number, since it uses less digits than its factorization.

643881100608 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44865 (or 44852 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 45.

The spelling of 643881100608 in words is "six hundred forty-three billion, eight hundred eighty-one million, one hundred thousand, six hundred eight".