643868921364 has 24 divisors (see below), whose sum is σ = 1503056092608. Its totient is φ = 214523648640.

The previous prime is 643868921351. The next prime is 643868921383. The reversal of 643868921364 is 463129868346.

It is a junction number, because it is equal to n+sod(n) for n = 643868921298 and 643868921307.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12388632 + ... + 12440495.

It is an arithmetic number, because the mean of its divisors is an integer number (62627337192).

Almost surely, 2^643868921364 is an apocalyptic number.

It is an amenable number.

643868921364 is an abundant number, since it is smaller than the sum of its proper divisors (859187171244).

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

643868921364 is a wasteful number, since it uses less digits than its factorization.

643868921364 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24831295 (or 24831293 counting only the distinct ones).

The product of its digits is 35831808, while the sum is 60.

The spelling of 643868921364 in words is "six hundred forty-three billion, eight hundred sixty-eight million, nine hundred twenty-one thousand, three hundred sixty-four".