18223221 has 8 divisors (see below), whose sum is σ = 24317440. Its totient is φ = 12138912.

The previous prime is 18223211. The next prime is 18223241. The reversal of 18223221 is 12232281.

It is a happy number.

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

It is not a de Polignac number, because 18223221 - 2⁶ = 18223157 is a prime.

It is a super-2 number, since 2×18223221² = 664171567229682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18223211) 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, 5361 + ... + 8073.

It is an arithmetic number, because the mean of its divisors is an integer number (3039680).

Almost surely, 2^18223221 is an apocalyptic number.

It is an amenable number.

18223221 is a deficient number, since it is larger than the sum of its proper divisors (6094219).

18223221 is a wasteful number, since it uses less digits than its factorization.

18223221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4955.

The product of its digits is 384, while the sum is 21.

The square root of 18223221 is about 4268.8664771810. The cubic root of 18223221 is about 263.1530334814.

The spelling of 18223221 in words is "eighteen million, two hundred twenty-three thousand, two hundred twenty-one".