18012209 has 16 divisors (see below), whose sum is σ = 19975680. Its totient is φ = 16174080.

The previous prime is 18012199. The next prime is 18012217. The reversal of 18012209 is 90221081.

It is a cyclic number.

It is not a de Polignac number, because 18012209 - 2⁴ = 18012193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18012259) 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, 30929 + ... + 31505.

It is an arithmetic number, because the mean of its divisors is an integer number (1248480).

Almost surely, 2^18012209 is an apocalyptic number.

18012209 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

18012209 is a deficient number, since it is larger than the sum of its proper divisors (1963471).

18012209 is a wasteful number, since it uses less digits than its factorization.

18012209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 680.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 18012209 is about 4244.0792876665. The cubic root of 18012209 is about 262.1333790509.

The spelling of 18012209 in words is "eighteen million, twelve thousand, two hundred nine".