19812099109 has 4 divisors (see below), whose sum is σ = 21613199040. Its totient is φ = 18010999180.

The previous prime is 19812099071. The next prime is 19812099127. The reversal of 19812099109 is 90199021891.

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 19812099109 - 2¹⁷ = 19811968037 is a prime.

It is a super-2 number, since 2×19812099109² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19812099179) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 900549949 + ... + 900549970.

It is an arithmetic number, because the mean of its divisors is an integer number (5403299760).

Almost surely, 2^19812099109 is an apocalyptic number.

It is an amenable number.

19812099109 is a deficient number, since it is larger than the sum of its proper divisors (1801099931).

19812099109 is a wasteful number, since it uses less digits than its factorization.

19812099109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1801099930.

The product of its (nonzero) digits is 104976, while the sum is 49.

The spelling of 19812099109 in words is "nineteen billion, eight hundred twelve million, ninety-nine thousand, one hundred nine".