643643901744 has 40 divisors (see below), whose sum is σ = 1669646140272. Its totient is φ = 213657722880.

The previous prime is 643643901743. The next prime is 643643901763. The reversal of 643643901744 is 447109346346.

It is not an unprimeable number, because it can be changed into a prime (643643901743) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27808449 + ... + 27831584.

Almost surely, 2^643643901744 is an apocalyptic number.

It is an amenable number.

643643901744 is an abundant number, since it is smaller than the sum of its proper divisors (1026002238528).

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

643643901744 is a wasteful number, since it uses less digits than its factorization.

643643901744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55640285 (or 55640279 counting only the distinct ones).

The product of its (nonzero) digits is 5225472, while the sum is 51.

The spelling of 643643901744 in words is "six hundred forty-three billion, six hundred forty-three million, nine hundred one thousand, seven hundred forty-four".