1221000020111 has 2 divisors, whose sum is σ = 1221000020112. Its totient is φ = 1221000020110.

The previous prime is 1221000020077. The next prime is 1221000020117. The reversal of 1221000020111 is 1110200001221.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221000020111 is a prime.

It is a super-2 number, since 2×1221000020111² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1221000020092 and 1221000020101.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221000020117) 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, 610500010055 + 610500010056.

It is an arithmetic number, because the mean of its divisors is an integer number (610500010056).

Almost surely, 2^{1221000020111} is an apocalyptic number.

1221000020111 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221000020111 is an equidigital number, since it uses as much as digits as its factorization.

1221000020111 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 1221000020111 its reverse (1110200001221), we get a palindrome (2331200021332).

The spelling of 1221000020111 in words is "one trillion, two hundred twenty-one billion, twenty thousand, one hundred eleven".