643403876 has 6 divisors (see below), whose sum is σ = 1125956790. Its totient is φ = 321701936.

The previous prime is 643403861. The next prime is 643403921. The reversal of 643403876 is 678304346.

It can be written as a sum of positive squares in only one way, i.e., 574081600 + 69322276 = 23960^2 + 8326^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80425481 + ... + 80425488.

It is an arithmetic number, because the mean of its divisors is an integer number (187659465).

Almost surely, 2^643403876 is an apocalyptic number.

It is an amenable number.

643403876 is a deficient number, since it is larger than the sum of its proper divisors (482552914).

643403876 is a wasteful number, since it uses less digits than its factorization.

643403876 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160850973 (or 160850971 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 41.

The square root of 643403876 is about 25365.4070734140. The cubic root of 643403876 is about 863.2989730399.

The spelling of 643403876 in words is "six hundred forty-three million, four hundred three thousand, eight hundred seventy-six".