12212561 has 2 divisors, whose sum is σ = 12212562. Its totient is φ = 12212560.

The previous prime is 12212549. The next prime is 12212569. The reversal of 12212561 is 16521221.

12212561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11182336 + 1030225 = 3344^2 + 1015^2 .

It is an emirp because it is prime and its reverse (16521221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12212561 - 2¹⁸ = 11950417 is a prime.

It is not a weakly prime, because it can be changed into another prime (12212569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6106280 + 6106281.

It is an arithmetic number, because the mean of its divisors is an integer number (6106281).

Almost surely, 2^12212561 is an apocalyptic number.

It is an amenable number.

12212561 is a deficient number, since it is larger than the sum of its proper divisors (1).

12212561 is an equidigital number, since it uses as much as digits as its factorization.

12212561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 240, while the sum is 20.

The square root of 12212561 is about 3494.6474786450. The cubic root of 12212561 is about 230.2867312427.

Adding to 12212561 its reverse (16521221), we get a palindrome (28733782).

The spelling of 12212561 in words is "twelve million, two hundred twelve thousand, five hundred sixty-one".