1212136561 has 2 divisors, whose sum is σ = 1212136562. Its totient is φ = 1212136560.

The previous prime is 1212136543. The next prime is 1212136591. The reversal of 1212136561 is 1656312121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 886550625 + 325585936 = 29775^2 + 18044^2 .

It is an emirp because it is prime and its reverse (1656312121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1212136561 - 2⁵ = 1212136529 is a prime.

It is not a weakly prime, because it can be changed into another prime (1212136511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606068280 + 606068281.

It is an arithmetic number, because the mean of its divisors is an integer number (606068281).

Almost surely, 2^1212136561 is an apocalyptic number.

It is an amenable number.

1212136561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1212136561 is an equidigital number, since it uses as much as digits as its factorization.

1212136561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2160, while the sum is 28.

The square root of 1212136561 is about 34815.7516219311. The cubic root of 1212136561 is about 1066.2290647141.

Adding to 1212136561 its reverse (1656312121), we get a palindrome (2868448682).

The spelling of 1212136561 in words is "one billion, two hundred twelve million, one hundred thirty-six thousand, five hundred sixty-one".