643404749443 has 24 divisors (see below), whose sum is σ = 690442531520. Its totient is φ = 599313686400.

The previous prime is 643404749441. The next prime is 643404749479. The reversal of 643404749443 is 344947404346.

It is a happy number.

It is not a de Polignac number, because 643404749443 - 2¹ = 643404749441 is a prime.

It is not an unprimeable number, because it can be changed into a prime (643404749441) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2945293 + ... + 3156193.

Almost surely, 2^643404749443 is an apocalyptic number.

643404749443 is a deficient number, since it is larger than the sum of its proper divisors (47037782077).

643404749443 is a wasteful number, since it uses less digits than its factorization.

643404749443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211099 (or 211076 counting only the distinct ones).

The product of its (nonzero) digits is 13934592, while the sum is 52.

The spelling of 643404749443 in words is "six hundred forty-three billion, four hundred four million, seven hundred forty-nine thousand, four hundred forty-three".