1221212111112 has 768 divisors, whose sum is σ = 4250984924160. Its totient is φ = 308559347712.

The previous prime is 1221212111111. The next prime is 1221212111131. The reversal of 1221212111112 is 2111112121221.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (1221212111111) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 3852403978 + ... + 3852404294.

It is an arithmetic number, because the mean of its divisors is an integer number (5535136620).

Almost surely, 2^{1221212111112} is an apocalyptic number.

1221212111112 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221212111112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2125492462080).

1221212111112 is an abundant number, since it is smaller than the sum of its proper divisors (3029772813048).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1221212111112 is a wasteful number, since it uses less digits than its factorization.

1221212111112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 662 (or 655 counting only the distinct ones).

The product of its digits is 32, while the sum is 18.

Adding to 1221212111112 its reverse (2111112121221), we get a palindrome (3332324232333).

The spelling of 1221212111112 in words is "one trillion, two hundred twenty-one billion, two hundred twelve million, one hundred eleven thousand, one hundred twelve".