12181009 has 4 divisors (see below), whose sum is σ = 12188016. Its totient is φ = 12174004.

The previous prime is 12180983. The next prime is 12181031. The reversal of 12181009 is 90018121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 12181009 - 2¹³ = 12172817 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12181079) 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 in 3 ways as a sum of consecutive naturals, for example, 1302 + ... + 5104.

It is an arithmetic number, because the mean of its divisors is an integer number (3047004).

Almost surely, 2^12181009 is an apocalyptic number.

It is an amenable number.

12181009 is a deficient number, since it is larger than the sum of its proper divisors (7007).

12181009 is an equidigital number, since it uses as much as digits as its factorization.

12181009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7006.

The product of its (nonzero) digits is 144, while the sum is 22.

The square root of 12181009 is about 3490.1302267967. The cubic root of 12181009 is about 230.0882396145.

It can be divided in two parts, 121 and 81009, that multiplied together give a palindrome (9802089).

The spelling of 12181009 in words is "twelve million, one hundred eighty-one thousand, nine".