19018809 has 12 divisors (see below), whose sum is σ = 28419300. Its totient is φ = 12241824.

The previous prime is 19018789. The next prime is 19018817. The reversal of 19018809 is 90881091.

It can be written as a sum of positive squares in 2 ways, for example, as 12531600 + 6487209 = 3540^2 + 2547^2 .

It is not a de Polignac number, because 19018809 - 2¹³ = 19010617 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19018889) 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, 36174 + ... + 36695.

It is an arithmetic number, because the mean of its divisors is an integer number (2368275).

Almost surely, 2^19018809 is an apocalyptic number.

It is an amenable number.

19018809 is a deficient number, since it is larger than the sum of its proper divisors (9400491).

19018809 is a wasteful number, since it uses less digits than its factorization.

19018809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72904 (or 72901 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 36.

The square root of 19018809 is about 4361.0559501112. The cubic root of 19018809 is about 266.9281884054.

The spelling of 19018809 in words is "nineteen million, eighteen thousand, eight hundred nine".