18356689 has 4 divisors (see below), whose sum is σ = 19768756. Its totient is φ = 16944624.

The previous prime is 18356683. The next prime is 18356731. The reversal of 18356689 is 98665381.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 98665381 = 367 ⋅268843.

It can be written as a sum of positive squares in 2 ways, for example, as 4068289 + 14288400 = 2017^2 + 3780^2 .

It is a cyclic number.

It is not a de Polignac number, because 18356689 - 2¹¹ = 18354641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18356683) 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, 706014 + ... + 706039.

It is an arithmetic number, because the mean of its divisors is an integer number (4942189).

Almost surely, 2^18356689 is an apocalyptic number.

It is an amenable number.

18356689 is a deficient number, since it is larger than the sum of its proper divisors (1412067).

18356689 is a wasteful number, since it uses less digits than its factorization.

18356689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1412066.

The product of its digits is 311040, while the sum is 46.

The square root of 18356689 is about 4284.4706790921. The cubic root of 18356689 is about 263.7939210939.

The spelling of 18356689 in words is "eighteen million, three hundred fifty-six thousand, six hundred eighty-nine".