19889660209 has 4 divisors (see below), whose sum is σ = 19890116416. Its totient is φ = 19889204004.

The previous prime is 19889660143. The next prime is 19889660213. The reversal of 19889660209 is 90206698891.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 19889660209 - 2¹¹ = 19889658161 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19889660239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 154869 + ... + 252514.

It is an arithmetic number, because the mean of its divisors is an integer number (4972529104).

Almost surely, 2^19889660209 is an apocalyptic number.

It is an amenable number.

19889660209 is a deficient number, since it is larger than the sum of its proper divisors (456207).

19889660209 is an equidigital number, since it uses as much as digits as its factorization.

19889660209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 456206.

The product of its (nonzero) digits is 3359232, while the sum is 58.

The spelling of 19889660209 in words is "nineteen billion, eight hundred eighty-nine million, six hundred sixty thousand, two hundred nine".