18018689 has 4 divisors (see below), whose sum is σ = 19404756. Its totient is φ = 16632624.

The previous prime is 18018661. The next prime is 18018697. The reversal of 18018689 is 98681081.

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 8898289 + 9120400 = 2983^2 + 3020^2 .

It is a cyclic number.

It is not a de Polignac number, because 18018689 - 2⁸ = 18018433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18018629) 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, 693014 + ... + 693039.

It is an arithmetic number, because the mean of its divisors is an integer number (4851189).

Almost surely, 2^18018689 is an apocalyptic number.

It is an amenable number.

18018689 is a deficient number, since it is larger than the sum of its proper divisors (1386067).

18018689 is a wasteful number, since it uses less digits than its factorization.

18018689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1386066.

The product of its (nonzero) digits is 27648, while the sum is 41.

The square root of 18018689 is about 4244.8426354813. The cubic root of 18018689 is about 262.1648099661.

The spelling of 18018689 in words is "eighteen million, eighteen thousand, six hundred eighty-nine".