643203621664436 has 18 divisors (see below), whose sum is σ = 1309378801245858. Its totient is φ = 275658694998960.

The previous prime is 643203621664411. The next prime is 643203621664463. The reversal of 643203621664436 is 634466126302346.

643203621664436 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 395685457720336 + 247518163944100 = 19891844^2 + 15732710^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1640825565275 + ... + 1640825565666.

It is an arithmetic number, because the mean of its divisors is an integer number (72743266735881).

Almost surely, 2^{643203621664436} is an apocalyptic number.

It is an amenable number.

643203621664436 is an abundant number, since it is smaller than the sum of its proper divisors (666175179581422).

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

643203621664436 is a wasteful number, since it uses less digits than its factorization.

643203621664436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3281651130959 (or 3281651130950 counting only the distinct ones).

The product of its (nonzero) digits is 53747712, while the sum is 56.

The spelling of 643203621664436 in words is "six hundred forty-three trillion, two hundred three billion, six hundred twenty-one million, six hundred sixty-four thousand, four hundred thirty-six".