1221020111 has 2 divisors, whose sum is σ = 1221020112. Its totient is φ = 1221020110.

The previous prime is 1221020093. The next prime is 1221020117. The reversal of 1221020111 is 1110201221.

It is a strong prime.

It is an emirp because it is prime and its reverse (1110201221) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221020111 is a prime.

It is a super-2 number, since 2×1221020111² = 2981780222932904642, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1221020092 and 1221020101.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221020117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610510055 + 610510056.

It is an arithmetic number, because the mean of its divisors is an integer number (610510056).

Almost surely, 2^1221020111 is an apocalyptic number.

1221020111 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221020111 is an equidigital number, since it uses as much as digits as its factorization.

1221020111 is an evil number, because the sum of its binary digits is even.

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

The square root of 1221020111 is about 34943.0981883404. The cubic root of 1221020111 is about 1068.8274665597.

Adding to 1221020111 its reverse (1110201221), we get a palindrome (2331221332).

The spelling of 1221020111 in words is "one billion, two hundred twenty-one million, twenty thousand, one hundred eleven".