18609221 has 4 divisors (see below), whose sum is σ = 18723552. Its totient is φ = 18494892.

The previous prime is 18609193. The next prime is 18609223. The reversal of 18609221 is 12290681.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18609221 - 2¹⁰ = 18608197 is a prime.

It is a super-3 number, since 3×18609221³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18609223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 56921 + ... + 57246.

It is an arithmetic number, because the mean of its divisors is an integer number (4680888).

Almost surely, 2^18609221 is an apocalyptic number.

It is an amenable number.

18609221 is a deficient number, since it is larger than the sum of its proper divisors (114331).

18609221 is a wasteful number, since it uses less digits than its factorization.

18609221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114330.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 18609221 is about 4313.8406321977. The cubic root of 18609221 is about 264.9980823405.

The spelling of 18609221 in words is "eighteen million, six hundred nine thousand, two hundred twenty-one".