212012561561 has 2 divisors, whose sum is σ = 212012561562. Its totient is φ = 212012561560.

The previous prime is 212012561521. The next prime is 212012561641. The reversal of 212012561561 is 165165210212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 209764000000 + 2248561561 = 458000^2 + 47419^2 .

It is a cyclic number.

It is not a de Polignac number, because 212012561561 - 2³⁰ = 210938819737 is a prime.

It is not a weakly prime, because it can be changed into another prime (212012561521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106006280780 + 106006280781.

It is an arithmetic number, because the mean of its divisors is an integer number (106006280781).

Almost surely, 2^212012561561 is an apocalyptic number.

It is an amenable number.

212012561561 is a deficient number, since it is larger than the sum of its proper divisors (1).

212012561561 is an equidigital number, since it uses as much as digits as its factorization.

212012561561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7200, while the sum is 32.

Adding to 212012561561 its reverse (165165210212), we get a palindrome (377177771773).

The spelling of 212012561561 in words is "two hundred twelve billion, twelve million, five hundred sixty-one thousand, five hundred sixty-one".