1221010111 has 2 divisors, whose sum is σ = 1221010112. Its totient is φ = 1221010110.

The previous prime is 1221010103. The next prime is 1221010117. The reversal of 1221010111 is 1110101221.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1221010111 - 2³ = 1221010103 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221010117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610505055 + 610505056.

It is an arithmetic number, because the mean of its divisors is an integer number (610505056).

Almost surely, 2^1221010111 is an apocalyptic number.

1221010111 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221010111 is an equidigital number, since it uses as much as digits as its factorization.

1221010111 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4, while the sum is 10.

The square root of 1221010111 is about 34942.9550982741. The cubic root of 1221010111 is about 1068.8245486979.

Adding to 1221010111 its reverse (1110101221), we get a palindrome (2331111332).

The spelling of 1221010111 in words is "one billion, two hundred twenty-one million, ten thousand, one hundred eleven".