643121036 has 12 divisors (see below), whose sum is σ = 1131118800. Its totient is φ = 319944240.

The previous prime is 643120967. The next prime is 643121057. The reversal of 643121036 is 630121346.

It is a junction number, because it is equal to n+sod(n) for n = 643120996 and 643121014.

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, 403175 + ... + 404766.

It is an arithmetic number, because the mean of its divisors is an integer number (94259900).

Almost surely, 2^643121036 is an apocalyptic number.

It is an amenable number.

643121036 is a deficient number, since it is larger than the sum of its proper divisors (487997764).

643121036 is a wasteful number, since it uses less digits than its factorization.

643121036 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 808144 (or 808142 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 26.

The square root of 643121036 is about 25359.8311508575. The cubic root of 643121036 is about 863.1724525763.

The spelling of 643121036 in words is "six hundred forty-three million, one hundred twenty-one thousand, thirty-six".