12122721 has 12 divisors (see below), whose sum is σ = 18857748. Its totient is φ = 7460064.

The previous prime is 12122659. The next prime is 12122723. The reversal of 12122721 is 12722121.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 1527696 + 10595025 = 1236^2 + 3255^2 .

It is not a de Polignac number, because 12122721 - 2⁶ = 12122657 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 12122694 and 12122703.

It is not an unprimeable number, because it can be changed into a prime (12122723) 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 11 ways as a sum of consecutive naturals, for example, 51690 + ... + 51923.

It is an arithmetic number, because the mean of its divisors is an integer number (1571479).

Almost surely, 2^12122721 is an apocalyptic number.

It is an amenable number.

12122721 is a deficient number, since it is larger than the sum of its proper divisors (6735027).

12122721 is a wasteful number, since it uses less digits than its factorization.

12122721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103632 (or 103629 counting only the distinct ones).

The product of its digits is 112, while the sum is 18.

The square root of 12122721 is about 3481.7698085887. The cubic root of 12122721 is about 229.7206501369.

Adding to 12122721 its reverse (12722121), we get a palindrome (24844842).

The spelling of 12122721 in words is "twelve million, one hundred twenty-two thousand, seven hundred twenty-one".