1212211103861 has 2 divisors, whose sum is σ = 1212211103862. Its totient is φ = 1212211103860.

The previous prime is 1212211103843. The next prime is 1212211103903. The reversal of 1212211103861 is 1683011122121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1209934000900 + 2277102961 = 1099970^2 + 47719^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1212211103861 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1212211103801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606105551930 + 606105551931.

It is an arithmetic number, because the mean of its divisors is an integer number (606105551931).

Almost surely, 2^{1212211103861} is an apocalyptic number.

It is an amenable number.

1212211103861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1212211103861 is an equidigital number, since it uses as much as digits as its factorization.

1212211103861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1152, while the sum is 29.

Adding to 1212211103861 its reverse (1683011122121), we get a palindrome (2895222225982).

The spelling of 1212211103861 in words is "one trillion, two hundred twelve billion, two hundred eleven million, one hundred three thousand, eight hundred sixty-one".