12311561 has 2 divisors, whose sum is σ = 12311562. Its totient is φ = 12311560.

The previous prime is 12311543. The next prime is 12311591. The reversal of 12311561 is 16511321.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8231161 + 4080400 = 2869^2 + 2020^2 .

It is an emirp because it is prime and its reverse (16511321) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12311561 is a prime.

It is not a weakly prime, because it can be changed into another prime (12311501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6155780 + 6155781.

It is an arithmetic number, because the mean of its divisors is an integer number (6155781).

Almost surely, 2^12311561 is an apocalyptic number.

It is an amenable number.

12311561 is a deficient number, since it is larger than the sum of its proper divisors (1).

12311561 is an equidigital number, since it uses as much as digits as its factorization.

12311561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 180, while the sum is 20.

The square root of 12311561 is about 3508.7834073935. The cubic root of 12311561 is about 230.9073233801.

Adding to 12311561 its reverse (16511321), we get a palindrome (28822882).

The spelling of 12311561 in words is "twelve million, three hundred eleven thousand, five hundred sixty-one".