18221371 has 16 divisors (see below), whose sum is σ = 21387520. Its totient is φ = 15202080.

The previous prime is 18221341. The next prime is 18221389. The reversal of 18221371 is 17312281.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 18221371 - 2⁵ = 18221339 is a prime.

It is a super-2 number, since 2×18221371² = 664036722239282, which contains 22 as substring.

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 (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 59200 + ... + 59506.

It is an arithmetic number, because the mean of its divisors is an integer number (1336720).

Almost surely, 2^18221371 is an apocalyptic number.

18221371 is a deficient number, since it is larger than the sum of its proper divisors (3166149).

18221371 is a wasteful number, since it uses less digits than its factorization.

18221371 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 514.

The product of its digits is 672, while the sum is 25.

The square root of 18221371 is about 4268.6497865250. The cubic root of 18221371 is about 263.1441281844.

The spelling of 18221371 in words is "eighteen million, two hundred twenty-one thousand, three hundred seventy-one".