1221212011111 has 2 divisors, whose sum is σ = 1221212011112. Its totient is φ = 1221212011110.

The previous prime is 1221212011057. The next prime is 1221212011139. The reversal of 1221212011111 is 1111102121221.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1221212011111 - 2⁷ = 1221212010983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221212011511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610606005555 + 610606005556.

It is an arithmetic number, because the mean of its divisors is an integer number (610606005556).

Almost surely, 2^{1221212011111} is an apocalyptic number.

1221212011111 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221212011111 is an equidigital number, since it uses as much as digits as its factorization.

1221212011111 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16, while the sum is 16.

Adding to 1221212011111 its reverse (1111102121221), we get a palindrome (2332314132332).

The spelling of 1221212011111 in words is "one trillion, two hundred twenty-one billion, two hundred twelve million, eleven thousand, one hundred eleven".