18337221 has 36 divisors (see below), whose sum is σ = 31560672. Its totient is φ = 10224144.

The previous prime is 18337219. The next prime is 18337247. The reversal of 18337221 is 12273381.

It is not a de Polignac number, because 18337221 - 2¹ = 18337219 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18337201) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 18480 + ... + 19446.

Almost surely, 2^18337221 is an apocalyptic number.

It is an amenable number.

18337221 is a deficient number, since it is larger than the sum of its proper divisors (13223451).

18337221 is a wasteful number, since it uses less digits than its factorization.

18337221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1030 (or 1020 counting only the distinct ones).

The product of its digits is 2016, while the sum is 27.

The square root of 18337221 is about 4282.1981504830. The cubic root of 18337221 is about 263.7006334535.

The spelling of 18337221 in words is "eighteen million, three hundred thirty-seven thousand, two hundred twenty-one".