18988289 has 8 divisors (see below), whose sum is σ = 19978728. Its totient is φ = 18023040.

The previous prime is 18988273. The next prime is 18988313. The reversal of 18988289 is 98288981.

It can be written as a sum of positive squares in 4 ways, for example, as 6150400 + 12837889 = 2480^2 + 3583^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18988289 - 2⁴ = 18988273 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 18988289.

It is not an unprimeable number, because it can be changed into a prime (18988219) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4742 + ... + 7775.

It is an arithmetic number, because the mean of its divisors is an integer number (2497341).

Almost surely, 2^18988289 is an apocalyptic number.

It is an amenable number.

18988289 is a deficient number, since it is larger than the sum of its proper divisors (990439).

18988289 is a wasteful number, since it uses less digits than its factorization.

18988289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12595.

The product of its digits is 663552, while the sum is 53.

The square root of 18988289 is about 4357.5553926485. Note that the first 3 decimals coincide. The cubic root of 18988289 is about 266.7853296541.

The spelling of 18988289 in words is "eighteen million, nine hundred eighty-eight thousand, two hundred eighty-nine".