18861909 has 16 divisors (see below), whose sum is σ = 28629504. Its totient is φ = 10934000.

The previous prime is 18861893. The next prime is 18861943. The reversal of 18861909 is 90916881.

It is not a de Polignac number, because 18861909 - 2⁴ = 18861893 is a prime.

It is a super-2 number, since 2×18861909² = 711543222248562, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18861949) 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, 11667 + ... + 13184.

It is an arithmetic number, because the mean of its divisors is an integer number (1789344).

Almost surely, 2^18861909 is an apocalyptic number.

It is an amenable number.

18861909 is a deficient number, since it is larger than the sum of its proper divisors (9767595).

18861909 is a wasteful number, since it uses less digits than its factorization.

18861909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24888.

The product of its (nonzero) digits is 31104, while the sum is 42.

The square root of 18861909 is about 4343.0299331227. The cubic root of 18861909 is about 266.1921322804.

The spelling of 18861909 in words is "eighteen million, eight hundred sixty-one thousand, nine hundred nine".