19868909 has 4 divisors (see below), whose sum is σ = 19948320. Its totient is φ = 19789500.

The previous prime is 19868897. The next prime is 19868939. The reversal of 19868909 is 90986891.

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 a de Polignac number, because none of the positive numbers 2^k-19868909 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 (19868939) 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, 39329 + ... + 39830.

It is an arithmetic number, because the mean of its divisors is an integer number (4987080).

Almost surely, 2^19868909 is an apocalyptic number.

It is an amenable number.

19868909 is a deficient number, since it is larger than the sum of its proper divisors (79411).

19868909 is an equidigital number, since it uses as much as digits as its factorization.

19868909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79410.

The product of its (nonzero) digits is 279936, while the sum is 50.

The square root of 19868909 is about 4457.4554400465. The cubic root of 19868909 is about 270.8474016413.

The spelling of 19868909 in words is "nineteen million, eight hundred sixty-eight thousand, nine hundred nine".