18221938 has 16 divisors (see below), whose sum is σ = 31965120. Its totient is φ = 7627536.

The previous prime is 18221899. The next prime is 18221953. The reversal of 18221938 is 83912281.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 14533 + ... + 15736.

It is an arithmetic number, because the mean of its divisors is an integer number (1997820).

Almost surely, 2^18221938 is an apocalyptic number.

18221938 is a deficient number, since it is larger than the sum of its proper divisors (13743182).

18221938 is a wasteful number, since it uses less digits than its factorization.

18221938 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30321.

The product of its digits is 6912, while the sum is 34.

The square root of 18221938 is about 4268.7162004518. The cubic root of 18221938 is about 263.1468576017.

The spelling of 18221938 in words is "eighteen million, two hundred twenty-one thousand, nine hundred thirty-eight".