643808106646 has 4 divisors (see below), whose sum is σ = 965712159972. Its totient is φ = 321904053322.

The previous prime is 643808106637. The next prime is 643808106659. The reversal of 643808106646 is 646601808346.

643808106646 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 junction number, because it is equal to n+sod(n) for n = 643808106593 and 643808106602.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160952026660 + ... + 160952026663.

It is an arithmetic number, because the mean of its divisors is an integer number (241428039993).

Almost surely, 2^643808106646 is an apocalyptic number.

643808106646 is a deficient number, since it is larger than the sum of its proper divisors (321904053326).

643808106646 is a wasteful number, since it uses less digits than its factorization.

643808106646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321904053325.

The product of its (nonzero) digits is 3981312, while the sum is 52.

The spelling of 643808106646 in words is "six hundred forty-three billion, eight hundred eight million, one hundred six thousand, six hundred forty-six".