18670221 has 12 divisors (see below), whose sum is σ = 27037920. Its totient is φ = 12414600.

The previous prime is 18670219. The next prime is 18670247. The reversal of 18670221 is 12207681.

It is not a de Polignac number, because 18670221 - 2¹ = 18670219 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18670271) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1296 + ... + 6246.

It is an arithmetic number, because the mean of its divisors is an integer number (2253160).

Almost surely, 2^18670221 is an apocalyptic number.

It is an amenable number.

18670221 is a deficient number, since it is larger than the sum of its proper divisors (8367699).

18670221 is a wasteful number, since it uses less digits than its factorization.

18670221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5376 (or 5373 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 18670221 is about 4320.9051135150. The cubic root of 18670221 is about 265.2873162385.

It can be divided in two parts, 186 and 70221, that added together give a palindrome (70407).

The spelling of 18670221 in words is "eighteen million, six hundred seventy thousand, two hundred twenty-one".