18209709 has 24 divisors (see below), whose sum is σ = 31100160. Its totient is φ = 10045728.

The previous prime is 18209693. The next prime is 18209753. The reversal of 18209709 is 90790281.

It is a happy number.

It is not a de Polignac number, because 18209709 - 2⁴ = 18209693 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18209759) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3157 + ... + 6810.

It is an arithmetic number, because the mean of its divisors is an integer number (1295840).

Almost surely, 2^18209709 is an apocalyptic number.

It is an amenable number.

18209709 is a deficient number, since it is larger than the sum of its proper divisors (12890451).

18209709 is a wasteful number, since it uses less digits than its factorization.

18209709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10009 (or 10006 counting only the distinct ones).

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

The square root of 18209709 is about 4267.2835621740. The cubic root of 18209709 is about 263.0879772367.

The spelling of 18209709 in words is "eighteen million, two hundred nine thousand, seven hundred nine".