643928479 has 4 divisors (see below), whose sum is σ = 645839584. Its totient is φ = 642017376.

The previous prime is 643928471. The next prime is 643928503. The reversal of 643928479 is 974829346.

It is a happy number.

643928479 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 643928479 - 2³ = 643928471 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643928471) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 955047 + ... + 955720.

It is an arithmetic number, because the mean of its divisors is an integer number (161459896).

Almost surely, 2^643928479 is an apocalyptic number.

643928479 is a deficient number, since it is larger than the sum of its proper divisors (1911105).

643928479 is a wasteful number, since it uses less digits than its factorization.

643928479 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1911104.

The product of its digits is 2612736, while the sum is 52.

The square root of 643928479 is about 25375.7458806633. The cubic root of 643928479 is about 863.5335412042.

The spelling of 643928479 in words is "six hundred forty-three million, nine hundred twenty-eight thousand, four hundred seventy-nine".