12181909 has 2 divisors, whose sum is σ = 12181910. Its totient is φ = 12181908.

The previous prime is 12181867. The next prime is 12181919. The reversal of 12181909 is 90918121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10923025 + 1258884 = 3305^2 + 1122^2 .

It is a cyclic number.

It is not a de Polignac number, because 12181909 - 2⁷ = 12181781 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12181919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6090954 + 6090955.

It is an arithmetic number, because the mean of its divisors is an integer number (6090955).

Almost surely, 2^12181909 is an apocalyptic number.

It is an amenable number.

12181909 is a deficient number, since it is larger than the sum of its proper divisors (1).

12181909 is an equidigital number, since it uses as much as digits as its factorization.

12181909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1296, while the sum is 31.

The square root of 12181909 is about 3490.2591594321. The cubic root of 12181909 is about 230.0939062035.

The spelling of 12181909 in words is "twelve million, one hundred eighty-one thousand, nine hundred nine".