12561917 has 2 divisors, whose sum is σ = 12561918. Its totient is φ = 12561916.

The previous prime is 12561911. The next prime is 12561931. The reversal of 12561917 is 71916521.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11689561 + 872356 = 3419^2 + 934^2 .

It is an emirp because it is prime and its reverse (71916521) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12561917 - 2¹⁰ = 12560893 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12561911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6280958 + 6280959.

It is an arithmetic number, because the mean of its divisors is an integer number (6280959).

Almost surely, 2^12561917 is an apocalyptic number.

It is an amenable number.

12561917 is a deficient number, since it is larger than the sum of its proper divisors (1).

12561917 is an equidigital number, since it uses as much as digits as its factorization.

12561917 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3780, while the sum is 32.

The square root of 12561917 is about 3544.2794754364. The cubic root of 12561917 is about 232.4620017294.

The spelling of 12561917 in words is "twelve million, five hundred sixty-one thousand, nine hundred seventeen".