18689138 has 8 divisors (see below), whose sum is σ = 30190188. Its totient is φ = 8625744.

The previous prime is 18689131. The next prime is 18689149. The reversal of 18689138 is 83198681.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 13010449 + 5678689 = 3607^2 + 2383^2 .

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

It is not an unprimeable number, because it can be changed into a prime (18689131) 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, 359381 + ... + 359432.

Almost surely, 2^18689138 is an apocalyptic number.

18689138 is a deficient number, since it is larger than the sum of its proper divisors (11501050).

18689138 is a wasteful number, since it uses less digits than its factorization.

18689138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 718828.

The product of its digits is 82944, while the sum is 44.

The square root of 18689138 is about 4323.0935682680. The cubic root of 18689138 is about 265.3768839372.

It can be divided in two parts, 18 and 689138, that multiplied together give a square (12404484 = 3522²).

The spelling of 18689138 in words is "eighteen million, six hundred eighty-nine thousand, one hundred thirty-eight".