19917109 has 4 divisors (see below), whose sum is σ = 20069280. Its totient is φ = 19764940.

The previous prime is 19917067. The next prime is 19917167. The reversal of 19917109 is 90171991.

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 19917109 - 2¹⁵ = 19884341 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19917169) 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, 75889 + ... + 76150.

It is an arithmetic number, because the mean of its divisors is an integer number (5017320).

Almost surely, 2^19917109 is an apocalyptic number.

It is an amenable number.

19917109 is a deficient number, since it is larger than the sum of its proper divisors (152171).

19917109 is a wasteful number, since it uses less digits than its factorization.

19917109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152170.

The product of its (nonzero) digits is 5103, while the sum is 37.

The square root of 19917109 is about 4462.8588371133. The cubic root of 19917109 is about 271.0662410750.

The spelling of 19917109 in words is "nineteen million, nine hundred seventeen thousand, one hundred nine".