18051209 has 8 divisors (see below), whose sum is σ = 19779552. Its totient is φ = 16337440.

The previous prime is 18051191. The next prime is 18051211. The reversal of 18051209 is 90215081.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18051209 is a prime.

It is a super-2 number, since 2×18051209² = 651692292723362, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18051289) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 959 + ... + 6084.

It is an arithmetic number, because the mean of its divisors is an integer number (2472444).

Almost surely, 2^18051209 is an apocalyptic number.

It is an amenable number.

18051209 is a deficient number, since it is larger than the sum of its proper divisors (1728343).

18051209 is a wasteful number, since it uses less digits than its factorization.

18051209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7287.

The product of its (nonzero) digits is 720, while the sum is 26.

The square root of 18051209 is about 4248.6714394031. The cubic root of 18051209 is about 262.3224328981.

The spelling of 18051209 in words is "eighteen million, fifty-one thousand, two hundred nine".