18190221 has 48 divisors (see below), whose sum is σ = 31026240. Its totient is φ = 9408000.

The previous prime is 18190127. The next prime is 18190223. The reversal of 18190221 is 12209181.

It is not a de Polignac number, because 18190221 - 2⁷ = 18190093 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18190191 and 18190200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18190223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 72346 + ... + 72596.

It is an arithmetic number, because the mean of its divisors is an integer number (646380).

Almost surely, 2^18190221 is an apocalyptic number.

It is an amenable number.

18190221 is a deficient number, since it is larger than the sum of its proper divisors (12836019).

18190221 is a wasteful number, since it uses less digits than its factorization.

18190221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 314 (or 307 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 24.

The square root of 18190221 is about 4264.9995310668. Note that the first 3 decimals coincide. The cubic root of 18190221 is about 262.9940916328.

The spelling of 18190221 in words is "eighteen million, one hundred ninety thousand, two hundred twenty-one".