18221293 has 4 divisors (see below), whose sum is σ = 18645088. Its totient is φ = 17797500.

The previous prime is 18221257. The next prime is 18221339. The reversal of 18221293 is 39212281.

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 18221293 - 2⁹ = 18220781 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18221213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 211833 + ... + 211918.

It is an arithmetic number, because the mean of its divisors is an integer number (4661272).

Almost surely, 2^18221293 is an apocalyptic number.

It is an amenable number.

18221293 is a deficient number, since it is larger than the sum of its proper divisors (423795).

18221293 is an equidigital number, since it uses as much as digits as its factorization.

18221293 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 423794.

The product of its digits is 1728, while the sum is 28.

The square root of 18221293 is about 4268.6406501368. The cubic root of 18221293 is about 263.1437527046.

The spelling of 18221293 in words is "eighteen million, two hundred twenty-one thousand, two hundred ninety-three".