12100721 has 2 divisors, whose sum is σ = 12100722. Its totient is φ = 12100720.

The previous prime is 12100717. The next prime is 12100727. The reversal of 12100721 is 12700121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6760000 + 5340721 = 2600^2 + 2311^2 .

It is a cyclic number.

It is not a de Polignac number, because 12100721 - 2² = 12100717 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 12100696 and 12100705.

It is not a weakly prime, because it can be changed into another prime (12100727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6050360 + 6050361.

It is an arithmetic number, because the mean of its divisors is an integer number (6050361).

Almost surely, 2^12100721 is an apocalyptic number.

It is an amenable number.

12100721 is a deficient number, since it is larger than the sum of its proper divisors (1).

12100721 is an equidigital number, since it uses as much as digits as its factorization.

12100721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28, while the sum is 14.

The square root of 12100721 is about 3478.6090611047. The cubic root of 12100721 is about 229.5816022947.

Adding to 12100721 its reverse (12700121), we get a palindrome (24800842).

It can be divided in two parts, 12100 and 721, that added together give a palindrome (12821).

The spelling of 12100721 in words is "twelve million, one hundred thousand, seven hundred twenty-one".