18136321 has 12 divisors (see below), whose sum is σ = 21176640. Its totient is φ = 15487080.

The previous prime is 18136319. The next prime is 18136357. The reversal of 18136321 is 12363181.

It is not a de Polignac number, because 18136321 - 2¹ = 18136319 is a prime.

It is a super-2 number, since 2×18136321² = 657852278830082, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18136361) 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, 17076 + ... + 18106.

It is an arithmetic number, because the mean of its divisors is an integer number (1764720).

Almost surely, 2^18136321 is an apocalyptic number.

It is an amenable number.

18136321 is a deficient number, since it is larger than the sum of its proper divisors (3040319).

18136321 is a wasteful number, since it uses less digits than its factorization.

18136321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1404 (or 1397 counting only the distinct ones).

The product of its digits is 864, while the sum is 25.

The square root of 18136321 is about 4258.6759679506. The cubic root of 18136321 is about 262.7340726955.

The spelling of 18136321 in words is "eighteen million, one hundred thirty-six thousand, three hundred twenty-one".