19639666806 has 32 divisors (see below), whose sum is σ = 43778828160. Its totient is φ = 5837175936.

The previous prime is 19639666777. The next prime is 19639666817. The reversal of 19639666806 is 60866693691.

It is a self number, because there is not a number n which added to its sum of digits gives 19639666806.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5065056 + ... + 5068931.

It is an arithmetic number, because the mean of its divisors is an integer number (1368088380).

Almost surely, 2^19639666806 is an apocalyptic number.

19639666806 is an abundant number, since it is smaller than the sum of its proper divisors (24139161354).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19639666806 is a wasteful number, since it uses less digits than its factorization.

19639666806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10134028.

The product of its (nonzero) digits is 15116544, while the sum is 60.

The spelling of 19639666806 in words is "nineteen billion, six hundred thirty-nine million, six hundred sixty-six thousand, eight hundred six".