643441409000 has 128 divisors (see below), whose sum is σ = 1622111006880. Its totient is φ = 237484800000.

The previous prime is 643441408963. The next prime is 643441409027. The reversal of 643441409000 is 904144346.

It can be written as a sum of positive squares in 16 ways, for example, as 266526452644 + 376914956356 = 516262^2 + 613934^2 .

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 31 ways as a sum of consecutive naturals, for example, 39004754 + ... + 39021246.

Almost surely, 2^643441409000 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 643441409000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (811055503440).

643441409000 is an abundant number, since it is smaller than the sum of its proper divisors (978669597880).

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

643441409000 is a wasteful number, since it uses less digits than its factorization.

643441409000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19528 (or 19514 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 35.

The spelling of 643441409000 in words is "six hundred forty-three billion, four hundred forty-one million, four hundred nine thousand".