12108721 has 4 divisors (see below), whose sum is σ = 12151792. Its totient is φ = 12065652.

The previous prime is 12108713. The next prime is 12108727. The reversal of 12108721 is 12780121.

12108721 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 Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 12108721 - 2³ = 12108713 is a prime.

It is a super-2 number, since 2×12108721² = 293242248511682, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12108692 and 12108701.

It is not an unprimeable number, because it can be changed into a prime (12108727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21111 + ... + 21676.

It is an arithmetic number, because the mean of its divisors is an integer number (3037948).

Almost surely, 2^12108721 is an apocalyptic number.

It is an amenable number.

12108721 is a deficient number, since it is larger than the sum of its proper divisors (43071).

12108721 is an equidigital number, since it uses as much as digits as its factorization.

12108721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43070.

The product of its (nonzero) digits is 224, while the sum is 22.

The square root of 12108721 is about 3479.7587560059. The cubic root of 12108721 is about 229.6321846310.

Adding to 12108721 its reverse (12780121), we get a palindrome (24888842).

The spelling of 12108721 in words is "twelve million, one hundred eight thousand, seven hundred twenty-one".