18988109 has 4 divisors (see below), whose sum is σ = 21700704. Its totient is φ = 16275516.

The previous prime is 18988097. The next prime is 18988111. The reversal of 18988109 is 90188981.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 90188981 = 3109 ⋅29009.

It is a cyclic number.

It is not a de Polignac number, because 18988109 - 2⁸ = 18987853 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 18988109.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18988199) 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, 1356287 + ... + 1356300.

It is an arithmetic number, because the mean of its divisors is an integer number (5425176).

Almost surely, 2^18988109 is an apocalyptic number.

It is an amenable number.

18988109 is a deficient number, since it is larger than the sum of its proper divisors (2712595).

18988109 is an equidigital number, since it uses as much as digits as its factorization.

18988109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2712594.

The product of its (nonzero) digits is 41472, while the sum is 44.

The square root of 18988109 is about 4357.5347388174. The cubic root of 18988109 is about 266.7844866518.

The spelling of 18988109 in words is "eighteen million, nine hundred eighty-eight thousand, one hundred nine".