12131661 has 4 divisors (see below), whose sum is σ = 16175552. Its totient is φ = 8087772.

The previous prime is 12131653. The next prime is 12131677. The reversal of 12131661 is 16613121.

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.

It is not a de Polignac number, because 12131661 - 2³ = 12131653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12131621) 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, 2021941 + ... + 2021946.

It is an arithmetic number, because the mean of its divisors is an integer number (4043888).

Almost surely, 2^12131661 is an apocalyptic number.

It is an amenable number.

12131661 is a deficient number, since it is larger than the sum of its proper divisors (4043891).

12131661 is an equidigital number, since it uses as much as digits as its factorization.

12131661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4043890.

The product of its digits is 216, while the sum is 21.

The square root of 12131661 is about 3483.0534018301. The cubic root of 12131661 is about 229.7771060535. Note that the first 3 decimals are identical.

Adding to 12131661 its reverse (16613121), we get a palindrome (28744782).

The spelling of 12131661 in words is "twelve million, one hundred thirty-one thousand, six hundred sixty-one".