12168516721 has 3 divisors (see below), whose sum is σ = 12168627033. Its totient is φ = 12168406410.

The previous prime is 12168516677. The next prime is 12168516733. The reversal of 12168516721 is 12761586121.

The square root of 12168516721 is 110311.

It is a perfect power (a square), and thus also a powerful number.

12168516721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 12168516721 - 2⁹ = 12168516209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12168516421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 55156 + ... + 165466.

It is an arithmetic number, because the mean of its divisors is an integer number (4056209011).

Almost surely, 2^12168516721 is an apocalyptic number.

12168516721 is the 110311-st square number.

12168516721 is the 55156-th centered octagonal number.

It is an amenable number.

12168516721 is a deficient number, since it is larger than the sum of its proper divisors (110312).

12168516721 is an frugal number, since it uses more digits than its factorization.

12168516721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220622 (or 110311 counting only the distinct ones).

The product of its digits is 40320, while the sum is 40.

The spelling of 12168516721 in words is "twelve billion, one hundred sixty-eight million, five hundred sixteen thousand, seven hundred twenty-one".