18022309 has 4 divisors (see below), whose sum is σ = 18208204. Its totient is φ = 17836416.

The previous prime is 18022297. The next prime is 18022327. The reversal of 18022309 is 90322081.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90322081 = 23 ⋅3927047.

It can be written as a sum of positive squares in 2 ways, for example, as 14861025 + 3161284 = 3855^2 + 1778^2 .

It is a cyclic number.

It is not a de Polignac number, because 18022309 - 2⁹ = 18021797 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18022379) 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, 92802 + ... + 92995.

It is an arithmetic number, because the mean of its divisors is an integer number (4552051).

Almost surely, 2^18022309 is an apocalyptic number.

It is an amenable number.

18022309 is a deficient number, since it is larger than the sum of its proper divisors (185895).

18022309 is an equidigital number, since it uses as much as digits as its factorization.

18022309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185894.

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

The square root of 18022309 is about 4245.2690138553. The cubic root of 18022309 is about 262.1823653140.

The spelling of 18022309 in words is "eighteen million, twenty-two thousand, three hundred nine".