12655561 has 2 divisors, whose sum is σ = 12655562. Its totient is φ = 12655560.

The previous prime is 12655553. The next prime is 12655567. The reversal of 12655561 is 16555621.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10497600 + 2157961 = 3240^2 + 1469^2 .

It is an emirp because it is prime and its reverse (16555621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12655561 - 2³ = 12655553 is a prime.

It is not a weakly prime, because it can be changed into another prime (12655567) 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, 6327780 + 6327781.

It is an arithmetic number, because the mean of its divisors is an integer number (6327781).

Almost surely, 2^12655561 is an apocalyptic number.

It is an amenable number.

12655561 is a deficient number, since it is larger than the sum of its proper divisors (1).

12655561 is an equidigital number, since it uses as much as digits as its factorization.

12655561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9000, while the sum is 31.

The square root of 12655561 is about 3557.4655304022. The cubic root of 12655561 is about 233.0382089647.

It can be divided in two parts, 1 and 2655561, that added together give a palindrome (2655562).

The spelling of 12655561 in words is "twelve million, six hundred fifty-five thousand, five hundred sixty-one".