18207909 has 20 divisors (see below), whose sum is σ = 28633440. Its totient is φ = 11498760.

The previous prime is 18207907. The next prime is 18207913. The reversal of 18207909 is 90970281.

It is a happy number.

It is not a de Polignac number, because 18207909 - 2¹ = 18207907 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18207907) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 4377 + ... + 7454.

It is an arithmetic number, because the mean of its divisors is an integer number (1431672).

Almost surely, 2^18207909 is an apocalyptic number.

18207909 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

18207909 is a deficient number, since it is larger than the sum of its proper divisors (10425531).

18207909 is a wasteful number, since it uses less digits than its factorization.

18207909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11862 (or 11853 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 36.

The square root of 18207909 is about 4267.0726499557. The cubic root of 18207909 is about 263.0793083454.

The spelling of 18207909 in words is "eighteen million, two hundred seven thousand, nine hundred nine".