643805688428 has 12 divisors (see below), whose sum is σ = 1287611376912. Its totient is φ = 275916723600.

The previous prime is 643805688419. The next prime is 643805688443. The reversal of 643805688428 is 824886508346.

643805688428 is an admirable number.

It is a super-2 number, since 2×643805688428² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11496530123 + ... + 11496530178.

It is an arithmetic number, because the mean of its divisors is an integer number (107300948076).

Almost surely, 2^643805688428 is an apocalyptic number.

It is an amenable number.

643805688428 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

643805688428 is a wasteful number, since it uses less digits than its factorization.

643805688428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22993060312 (or 22993060310 counting only the distinct ones).

The product of its (nonzero) digits is 70778880, while the sum is 62.

The spelling of 643805688428 in words is "six hundred forty-three billion, eight hundred five million, six hundred eighty-eight thousand, four hundred twenty-eight".