18609218 has 4 divisors (see below), whose sum is σ = 27913830. Its totient is φ = 9304608.

The previous prime is 18609193. The next prime is 18609223. The reversal of 18609218 is 81290681.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 13053769 + 5555449 = 3613^2 + 2357^2 .

It is a super-3 number, since 3×18609218³ (a number of 23 digits) contains 333 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4652303 + ... + 4652306.

Almost surely, 2^18609218 is an apocalyptic number.

18609218 is a deficient number, since it is larger than the sum of its proper divisors (9304612).

18609218 is an equidigital number, since it uses as much as digits as its factorization.

18609218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9304611.

The product of its (nonzero) digits is 6912, while the sum is 35.

The square root of 18609218 is about 4313.8402844797. The cubic root of 18609218 is about 264.9980681003.

Adding to 18609218 its reverse (81290681), we get a palindrome (99899899).

The spelling of 18609218 in words is "eighteen million, six hundred nine thousand, two hundred eighteen".