18120321 has 8 divisors (see below), whose sum is σ = 26844960. Its totient is φ = 12080196.

The previous prime is 18120307. The next prime is 18120353. The reversal of 18120321 is 12302181.

It is not a de Polignac number, because 18120321 - 2¹⁴ = 18103937 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18120294 and 18120303.

It is not an unprimeable number, because it can be changed into a prime (18120391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 335535 + ... + 335588.

It is an arithmetic number, because the mean of its divisors is an integer number (3355620).

Almost surely, 2^18120321 is an apocalyptic number.

It is an amenable number.

18120321 is a deficient number, since it is larger than the sum of its proper divisors (8724639).

18120321 is an equidigital number, since it uses as much as digits as its factorization.

18120321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 671132 (or 671126 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 18120321 is about 4256.7970353307. The cubic root of 18120321 is about 262.6567879665.

It can be divided in two parts, 181 and 20321, that added together give a palindrome (20502).

The spelling of 18120321 in words is "eighteen million, one hundred twenty thousand, three hundred twenty-one".