19999999919 has 4 divisors (see below), whose sum is σ = 20003059440. Its totient is φ = 19996940400.

The previous prime is 19999999913. The next prime is 19999999939. The reversal of 19999999919 is 91999999991.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 19999999919 - 2²⁴ = 19983222703 is a prime.

It is a super-2 number, since 2×19999999919² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19999999913) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1519934 + ... + 1533035.

It is an arithmetic number, because the mean of its divisors is an integer number (5000764860).

Almost surely, 2^19999999919 is an apocalyptic number.

19999999919 is a deficient number, since it is larger than the sum of its proper divisors (3059521).

19999999919 is an equidigital number, since it uses as much as digits as its factorization.

19999999919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3059520.

The product of its digits is 387420489, while the sum is 83.

Adding to 19999999919 its sum of digits (83), we get a palindrome (20000000002).

The spelling of 19999999919 in words is "nineteen billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred nineteen".