12116721 has 4 divisors (see below), whose sum is σ = 16155632. Its totient is φ = 8077812.

The previous prime is 12116719. The next prime is 12116729. The reversal of 12116721 is 12761121.

It is a happy number.

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 an emirpimes, since its reverse is a distinct semiprime: 12761121 = 3 ⋅4253707.

It is not a de Polignac number, because 12116721 - 2¹ = 12116719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12116729) 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, 2019451 + ... + 2019456.

It is an arithmetic number, because the mean of its divisors is an integer number (4038908).

Almost surely, 2^12116721 is an apocalyptic number.

It is an amenable number.

12116721 is a deficient number, since it is larger than the sum of its proper divisors (4038911).

12116721 is an equidigital number, since it uses as much as digits as its factorization.

12116721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4038910.

The product of its digits is 168, while the sum is 21.

The square root of 12116721 is about 3480.9080711791. The cubic root of 12116721 is about 229.6827446931.

Adding to 12116721 its reverse (12761121), we get a palindrome (24877842).

The spelling of 12116721 in words is "twelve million, one hundred sixteen thousand, seven hundred twenty-one".