18688109 has 8 divisors (see below), whose sum is σ = 20692128. Its totient is φ = 16734960.

The previous prime is 18688091. The next prime is 18688139. The reversal of 18688109 is 90188681.

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

It is not a de Polignac number, because 18688109 - 2¹² = 18684013 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 (18688139) 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, 11942 + ... + 13415.

It is an arithmetic number, because the mean of its divisors is an integer number (2586516).

Almost surely, 2^18688109 is an apocalyptic number.

It is an amenable number.

18688109 is a deficient number, since it is larger than the sum of its proper divisors (2004019).

18688109 is a wasteful number, since it uses less digits than its factorization.

18688109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25435.

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

The square root of 18688109 is about 4322.9745546325. The cubic root of 18688109 is about 265.3720134107.

The spelling of 18688109 in words is "eighteen million, six hundred eighty-eight thousand, one hundred nine".