12216181 has 2 divisors, whose sum is σ = 12216182. Its totient is φ = 12216180.

The previous prime is 12216173. The next prime is 12216187. The reversal of 12216181 is 18161221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12215025 + 1156 = 3495^2 + 34^2 .

It is a cyclic number.

It is not a de Polignac number, because 12216181 - 2³ = 12216173 is a prime.

It is a super-2 number, since 2×12216181² = 298470156449522, which contains 22 as substring.

It is equal to p₈₀₁₂₉₂ and since 12216181 and 801292 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12216187) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6108090 + 6108091.

It is an arithmetic number, because the mean of its divisors is an integer number (6108091).

Almost surely, 2^12216181 is an apocalyptic number.

It is an amenable number.

12216181 is a deficient number, since it is larger than the sum of its proper divisors (1).

12216181 is an equidigital number, since it uses as much as digits as its factorization.

12216181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 192, while the sum is 22.

The square root of 12216181 is about 3495.1653752004. The cubic root of 12216181 is about 230.3094825616.

The spelling of 12216181 in words is "twelve million, two hundred sixteen thousand, one hundred eighty-one".