19105209 has 12 divisors (see below), whose sum is σ = 28342756. Its totient is φ = 12392352.

The previous prime is 19105199. The next prime is 19105211. The reversal of 19105209 is 90250191.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 17665209 + 1440000 = 4203^2 + 1200^2 .

It is not a de Polignac number, because 19105209 - 2⁷ = 19105081 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19105309) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 28354 + ... + 29019.

Almost surely, 2^19105209 is an apocalyptic number.

It is an amenable number.

19105209 is a deficient number, since it is larger than the sum of its proper divisors (9237547).

19105209 is a wasteful number, since it uses less digits than its factorization.

19105209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57416 (or 57413 counting only the distinct ones).

The product of its (nonzero) digits is 810, while the sum is 27.

The square root of 19105209 is about 4370.9505831112. The cubic root of 19105209 is about 267.3317846538.

The spelling of 19105209 in words is "nineteen million, one hundred five thousand, two hundred nine".