18393221 has 16 divisors (see below), whose sum is σ = 23725440. Its totient is φ = 13836480.

The previous prime is 18393203. The next prime is 18393223. The reversal of 18393221 is 12239381.

It is not a de Polignac number, because 18393221 - 2⁶ = 18393157 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18393223) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1886 + ... + 6351.

It is an arithmetic number, because the mean of its divisors is an integer number (1482840).

Almost surely, 2^18393221 is an apocalyptic number.

18393221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18393221 is a deficient number, since it is larger than the sum of its proper divisors (5332219).

18393221 is a wasteful number, since it uses less digits than its factorization.

18393221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8284.

The product of its digits is 2592, while the sum is 29.

The square root of 18393221 is about 4288.7318638497. The cubic root of 18393221 is about 263.9687989220.

The spelling of 18393221 in words is "eighteen million, three hundred ninety-three thousand, two hundred twenty-one".