18390389 has 4 divisors (see below), whose sum is σ = 18402924. Its totient is φ = 18377856.

The previous prime is 18390367. The next prime is 18390397. The reversal of 18390389 is 98309381.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 98309381 = 6121 ⋅16061.

It can be written as a sum of positive squares in 2 ways, for example, as 11785489 + 6604900 = 3433^2 + 2570^2 .

It is a cyclic number.

It is not a de Polignac number, because 18390389 - 2¹² = 18386293 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 (18390289) 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, 3722 + ... + 7115.

It is an arithmetic number, because the mean of its divisors is an integer number (4600731).

Almost surely, 2^18390389 is an apocalyptic number.

It is an amenable number.

18390389 is a deficient number, since it is larger than the sum of its proper divisors (12535).

18390389 is a wasteful number, since it uses less digits than its factorization.

18390389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12534.

The product of its (nonzero) digits is 46656, while the sum is 41.

The square root of 18390389 is about 4288.4016836113. The cubic root of 18390389 is about 263.9552504883.

The spelling of 18390389 in words is "eighteen million, three hundred ninety thousand, three hundred eighty-nine".