181819109 has 2 divisors, whose sum is σ = 181819110. Its totient is φ = 181819108.

The previous prime is 181819103. The next prime is 181819159. The reversal of 181819109 is 901918181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 151536100 + 30283009 = 12310^2 + 5503^2 .

It is a cyclic number.

It is not a de Polignac number, because 181819109 - 2¹² = 181815013 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (181819103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90909554 + 90909555.

It is an arithmetic number, because the mean of its divisors is an integer number (90909555).

Almost surely, 2^181819109 is an apocalyptic number.

It is an amenable number.

181819109 is a deficient number, since it is larger than the sum of its proper divisors (1).

181819109 is an equidigital number, since it uses as much as digits as its factorization.

181819109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 38.

The square root of 181819109 is about 13484.0316300430. The cubic root of 181819109 is about 566.5172979244.

The spelling of 181819109 in words is "one hundred eighty-one million, eight hundred nineteen thousand, one hundred nine".