12635221 has 2 divisors, whose sum is σ = 12635222. Its totient is φ = 12635220.

The previous prime is 12635219. The next prime is 12635243. The reversal of 12635221 is 12253621.

It is an a-pointer prime, because the next prime (12635243) can be obtained adding 12635221 to its sum of digits (22).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12152196 + 483025 = 3486^2 + 695^2 .

It is an emirp because it is prime and its reverse (12253621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12635221 - 2¹ = 12635219 is a prime.

Together with 12635219, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 12635192 and 12635201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12635251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6317610 + 6317611.

It is an arithmetic number, because the mean of its divisors is an integer number (6317611).

Almost surely, 2^12635221 is an apocalyptic number.

It is an amenable number.

12635221 is a deficient number, since it is larger than the sum of its proper divisors (1).

12635221 is an equidigital number, since it uses as much as digits as its factorization.

12635221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 720, while the sum is 22.

The square root of 12635221 is about 3554.6056040017. The cubic root of 12635221 is about 232.9132957925.

Adding to 12635221 its reverse (12253621), we get a palindrome (24888842).

The spelling of 12635221 in words is "twelve million, six hundred thirty-five thousand, two hundred twenty-one".