19968209 has 8 divisors (see below), whose sum is σ = 20881152. Its totient is φ = 19059040.

The previous prime is 19968203. The next prime is 19968229. The reversal of 19968209 is 90286991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19968209 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 19968209.

It is not an unprimeable number, because it can be changed into a prime (19968203) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20477 + ... + 21429.

It is an arithmetic number, because the mean of its divisors is an integer number (2610144).

Almost surely, 2^19968209 is an apocalyptic number.

It is an amenable number.

19968209 is a deficient number, since it is larger than the sum of its proper divisors (912943).

19968209 is an equidigital number, since it uses as much as digits as its factorization.

With its successor (19968210) it forms a Ruth-Aaron pair, since the sum of their prime factors is the same (1887).

19968209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1887.

The product of its (nonzero) digits is 69984, while the sum is 44.

The square root of 19968209 is about 4468.5801995712. The cubic root of 19968209 is about 271.2978619699.

The spelling of 19968209 in words is "nineteen million, nine hundred sixty-eight thousand, two hundred nine".