18180109 has 4 divisors (see below), whose sum is σ = 18191740. Its totient is φ = 18168480.

The previous prime is 18180077. The next prime is 18180161. The reversal of 18180109 is 90108181.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 1898884 + 16281225 = 1378^2 + 4035^2 .

It is a cyclic number.

It is not a de Polignac number, because 18180109 - 2⁵ = 18180077 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 (18180199) 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, 3024 + ... + 6745.

It is an arithmetic number, because the mean of its divisors is an integer number (4547935).

Almost surely, 2^18180109 is an apocalyptic number.

It is an amenable number.

18180109 is a deficient number, since it is larger than the sum of its proper divisors (11631).

18180109 is an equidigital number, since it uses as much as digits as its factorization.

18180109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11630.

The product of its (nonzero) digits is 576, while the sum is 28.

The square root of 18180109 is about 4263.8139030685. The cubic root of 18180109 is about 262.9453495240.

The spelling of 18180109 in words is "eighteen million, one hundred eighty thousand, one hundred nine".