181396109 has 2 divisors, whose sum is σ = 181396110. Its totient is φ = 181396108.

The previous prime is 181396099. The next prime is 181396129. The reversal of 181396109 is 901693181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 138532900 + 42863209 = 11770^2 + 6547^2 .

It is an emirp because it is prime and its reverse (901693181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 181396109 - 2²⁰ = 180347533 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (181396129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90698054 + 90698055.

It is an arithmetic number, because the mean of its divisors is an integer number (90698055).

Almost surely, 2^181396109 is an apocalyptic number.

It is an amenable number.

181396109 is a deficient number, since it is larger than the sum of its proper divisors (1).

181396109 is an equidigital number, since it uses as much as digits as its factorization.

181396109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11664, while the sum is 38.

The square root of 181396109 is about 13468.3372767391. The cubic root of 181396109 is about 566.0776248590.

The spelling of 181396109 in words is "one hundred eighty-one million, three hundred ninety-six thousand, one hundred nine".