18216227 has 4 divisors (see below), whose sum is σ = 18262056. Its totient is φ = 18170400.

The previous prime is 18216223. The next prime is 18216229. The reversal of 18216227 is 72261281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 72261281 = 557 ⋅129733.

It is a cyclic number.

It is not a de Polignac number, because 18216227 - 2² = 18216223 is a prime.

It is a super-2 number, since 2×18216227² = 663661852231058, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18216227.

It is not an unprimeable number, because it can be changed into a prime (18216221) 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, 22313 + ... + 23114.

It is an arithmetic number, because the mean of its divisors is an integer number (4565514).

Almost surely, 2^18216227 is an apocalyptic number.

18216227 is a deficient number, since it is larger than the sum of its proper divisors (45829).

18216227 is an equidigital number, since it uses as much as digits as its factorization.

18216227 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45828.

The product of its digits is 2688, while the sum is 29.

The square root of 18216227 is about 4268.0472115477. The cubic root of 18216227 is about 263.1193634765.

The spelling of 18216227 in words is "eighteen million, two hundred sixteen thousand, two hundred twenty-seven".