18312389 has 4 divisors (see below), whose sum is σ = 18325356. Its totient is φ = 18299424.

The previous prime is 18312353. The next prime is 18312397. The reversal of 18312389 is 98321381.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8168164 + 10144225 = 2858^2 + 3185^2 .

It is a cyclic number.

It is not a de Polignac number, because 18312389 - 2¹² = 18308293 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18312319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4064 + ... + 7289.

It is an arithmetic number, because the mean of its divisors is an integer number (4581339).

Almost surely, 2^18312389 is an apocalyptic number.

It is an amenable number.

18312389 is a deficient number, since it is larger than the sum of its proper divisors (12967).

18312389 is a wasteful number, since it uses less digits than its factorization.

18312389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12966.

The product of its digits is 10368, while the sum is 35.

The square root of 18312389 is about 4279.2977227578. The cubic root of 18312389 is about 263.5815464848.

The spelling of 18312389 in words is "eighteen million, three hundred twelve thousand, three hundred eighty-nine".