18685199 has 4 divisors (see below), whose sum is σ = 20122536. Its totient is φ = 17247864.

The previous prime is 18685187. The next prime is 18685213. The reversal of 18685199 is 99158681.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 99158681 = 23 ⋅4311247.

It is a cyclic number.

It is not a de Polignac number, because 18685199 - 2⁸ = 18684943 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 (18685099) 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, 718649 + ... + 718674.

It is an arithmetic number, because the mean of its divisors is an integer number (5030634).

Almost surely, 2^18685199 is an apocalyptic number.

18685199 is a deficient number, since it is larger than the sum of its proper divisors (1437337).

18685199 is a wasteful number, since it uses less digits than its factorization.

18685199 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1437336.

The product of its digits is 155520, while the sum is 47.

The square root of 18685199 is about 4322.6379677230. The cubic root of 18685199 is about 265.3582386508.

The spelling of 18685199 in words is "eighteen million, six hundred eighty-five thousand, one hundred ninety-nine".