18573221 has 4 divisors (see below), whose sum is σ = 18587244. Its totient is φ = 18559200.

The previous prime is 18573211. The next prime is 18573263. The reversal of 18573221 is 12237581.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12348196 + 6225025 = 3514^2 + 2495^2 .

It is a cyclic number.

It is not a de Polignac number, because 18573221 - 2⁶ = 18573157 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18573211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4790 + ... + 7751.

It is an arithmetic number, because the mean of its divisors is an integer number (4646811).

Almost surely, 2^18573221 is an apocalyptic number.

It is an amenable number.

18573221 is a deficient number, since it is larger than the sum of its proper divisors (14023).

18573221 is a wasteful number, since it uses less digits than its factorization.

18573221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14022.

The product of its digits is 3360, while the sum is 29.

The square root of 18573221 is about 4309.6659963389. The cubic root of 18573221 is about 264.8270902406.

The spelling of 18573221 in words is "eighteen million, five hundred seventy-three thousand, two hundred twenty-one".