1221111110123 has 2 divisors, whose sum is σ = 1221111110124. Its totient is φ = 1221111110122.

The previous prime is 1221111110071. The next prime is 1221111110207. The reversal of 1221111110123 is 3210111111221.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1221111110123 - 2²⁰ = 1221110061547 is a prime.

It is a super-2 number, since 2×1221111110123² (a number of 25 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (1221111160123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610555555061 + 610555555062.

It is an arithmetic number, because the mean of its divisors is an integer number (610555555062).

Almost surely, 2^{1221111110123} is an apocalyptic number.

1221111110123 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221111110123 is an equidigital number, since it uses as much as digits as its factorization.

1221111110123 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24, while the sum is 17.

Adding to 1221111110123 its reverse (3210111111221), we get a palindrome (4431222221344).

The spelling of 1221111110123 in words is "one trillion, two hundred twenty-one billion, one hundred eleven million, one hundred ten thousand, one hundred twenty-three".