18221586 has 16 divisors (see below), whose sum is σ = 38587104. Its totient is φ = 5716544.

The previous prime is 18221563. The next prime is 18221611. The reversal of 18221586 is 68512281.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 89220 + ... + 89423.

It is an arithmetic number, because the mean of its divisors is an integer number (2411694).

Almost surely, 2^18221586 is an apocalyptic number.

18221586 is an abundant number, since it is smaller than the sum of its proper divisors (20365518).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18221586 is a wasteful number, since it uses less digits than its factorization.

18221586 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178665.

The product of its digits is 7680, while the sum is 33.

The square root of 18221586 is about 4268.6749700580. The cubic root of 18221586 is about 263.1451631553.

The spelling of 18221586 in words is "eighteen million, two hundred twenty-one thousand, five hundred eighty-six".