18221344 has 12 divisors (see below), whose sum is σ = 35873334. Its totient is φ = 9110656.

The previous prime is 18221341. The next prime is 18221389. The reversal of 18221344 is 44312281.

It can be written as a sum of positive squares in only one way, i.e., 16810000 + 1411344 = 4100^2 + 1188^2 .

It is not an unprimeable number, because it can be changed into a prime (18221341) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 284677 + ... + 284740.

Almost surely, 2^18221344 is an apocalyptic number.

It is an amenable number.

18221344 is a deficient number, since it is larger than the sum of its proper divisors (17651990).

18221344 is an equidigital number, since it uses as much as digits as its factorization.

18221344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 569427 (or 569419 counting only the distinct ones).

The product of its digits is 1536, while the sum is 25.

The square root of 18221344 is about 4268.6466239313. The cubic root of 18221344 is about 263.1439982107.

The spelling of 18221344 in words is "eighteen million, two hundred twenty-one thousand, three hundred forty-four".