181138109 has 2 divisors, whose sum is σ = 181138110. Its totient is φ = 181138108.

The previous prime is 181138081. The next prime is 181138129. The reversal of 181138109 is 901831181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 113848900 + 67289209 = 10670^2 + 8203^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-181138109 is a prime.

It is a super-2 number, since 2×181138109² = 65622029064191762, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (181138129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90569054 + 90569055.

It is an arithmetic number, because the mean of its divisors is an integer number (90569055).

Almost surely, 2^181138109 is an apocalyptic number.

It is an amenable number.

181138109 is a deficient number, since it is larger than the sum of its proper divisors (1).

181138109 is an equidigital number, since it uses as much as digits as its factorization.

181138109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 32.

The square root of 181138109 is about 13458.7558488889. The cubic root of 181138109 is about 565.8091197916.

The spelling of 181138109 in words is "one hundred eighty-one million, one hundred thirty-eight thousand, one hundred nine".