18685909 has 16 divisors (see below), whose sum is σ = 20905920. Its totient is φ = 16698000.

The previous prime is 18685871. The next prime is 18685957. The reversal of 18685909 is 90958681.

It is not a de Polignac number, because 18685909 - 2⁷ = 18685781 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 (18685969) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 134362 + ... + 134500.

It is an arithmetic number, because the mean of its divisors is an integer number (1306620).

Almost surely, 2^18685909 is an apocalyptic number.

It is an amenable number.

18685909 is a deficient number, since it is larger than the sum of its proper divisors (2220011).

18685909 is a wasteful number, since it uses less digits than its factorization.

18685909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 273 (or 251 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 46.

The square root of 18685909 is about 4322.7200927194. The cubic root of 18685909 is about 265.3615996348.

It can be divided in two parts, 1868 and 5909, that added together give a palindrome (7777).

The spelling of 18685909 in words is "eighteen million, six hundred eighty-five thousand, nine hundred nine".