12020020211561 has 2 divisors, whose sum is σ = 12020020211562. Its totient is φ = 12020020211560.

The previous prime is 12020020211533. The next prime is 12020020211579. The reversal of 12020020211561 is 16511202002021.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7115124121561 + 4904896090000 = 2667419^2 + 2214700^2 .

It is an emirp because it is prime and its reverse (16511202002021) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12020020211561 - 2¹⁸ = 12020019949417 is a prime.

It is not a weakly prime, because it can be changed into another prime (12020020211581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6010010105780 + 6010010105781.

It is an arithmetic number, because the mean of its divisors is an integer number (6010010105781).

Almost surely, 2^{12020020211561} is an apocalyptic number.

It is an amenable number.

12020020211561 is a deficient number, since it is larger than the sum of its proper divisors (1).

12020020211561 is an equidigital number, since it uses as much as digits as its factorization.

12020020211561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 480, while the sum is 23.

Adding to 12020020211561 its reverse (16511202002021), we get a palindrome (28531222213582).

The spelling of 12020020211561 in words is "twelve trillion, twenty billion, twenty million, two hundred eleven thousand, five hundred sixty-one".