12210721 has 2 divisors, whose sum is σ = 12210722. Its totient is φ = 12210720.

The previous prime is 12210691. The next prime is 12210727. The reversal of 12210721 is 12701221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11971600 + 239121 = 3460^2 + 489^2 .

It is a cyclic number.

It is not a de Polignac number, because 12210721 - 2⁵ = 12210689 is a prime.

It is a nialpdrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 12210695 and 12210704.

It is not a weakly prime, because it can be changed into another prime (12210727) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6105360 + 6105361.

It is an arithmetic number, because the mean of its divisors is an integer number (6105361).

Almost surely, 2^12210721 is an apocalyptic number.

It is an amenable number.

12210721 is a deficient number, since it is larger than the sum of its proper divisors (1).

12210721 is an equidigital number, since it uses as much as digits as its factorization.

12210721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 56, while the sum is 16.

The square root of 12210721 is about 3494.3842089845. The cubic root of 12210721 is about 230.2751653129.

Adding to 12210721 its reverse (12701221), we get a palindrome (24911942).

The spelling of 12210721 in words is "twelve million, two hundred ten thousand, seven hundred twenty-one".